高濃度 塗工液의 流動特性이 塗工紙 品質에 미치는 影響

劉成鍾 강원대학교 2008 국내박사

본 논문에서는 고농도 도공(high solid coating)의 기술 개발을 위한 연구결과에 대해서 기술하고 있다. 연구의 목표는 고농도 도공에 미치는 제반 영향인자에 대한 고찰을 통해 고농도 도공의 최적화를 위한 조절변수제어(adjustable variable control) 기술을 확보하는 것에 있다. 궁극적인 연구의 목적은 고농도 도공 기술의 완성도 향상에 의해 도공속도 고속화에 의한 생산성향상, 도공지 품질향상에 의한 경쟁력 제고, 공정비용 및 도공지 원단위 절감을 통한 경제성 향상을 견인하는데 있다. 본 논문에서는 고농도 도공액 설계를 위한 영향인자 고찰을 위해 도공액 구성 물질(안료, 바인더 및 유동성 조절제)의 특성에 의한 도공액의 유동특성 및 침투특성과 같은 제반 물리적 성질의 변화와 이에 따른 도공지 물성의 변화에 대해서 고찰하였다. 또한 고농도 도공액의 설계 변경시 피 도피체인 원지의 특성에 따른 상호작용 및 부합 특이성에 대해서 관찰하였다. 고농도 도공시 재설정이 요구되는 공정변수(도공속도 및 건조조건)에 의한 도공적성 및 도공지 품질에 미치는 영향에 대해서 관찰하였다. 이상의 연구를 통해 얻는 결과를 요약하면 아래와 같다. 안료 중 clay의 비율을 감소시킨 경우에도 고농도 도공을 통해 도공지 품질을 개선할 수 있었다. 중질탄산칼슘의 비율이 증가됨에 따라 도공지의 백색도가 상승되었으며, 이에 따른 형광염료 절감으로 인해 색상 견뢰도가 향상되었다. 고농도 도공에 있어 팽윤형 증점제인 CMC, HEC, 전분 그리고 알칼리 팽윤형 합성 증점제는 고농도 고속 도공에 적합하지 않은 것으로 나타났다. 이들 유동성 조절제(rheology modifier)군은 도공액 내의 물 분자를 부위별로 불균일하게 분포시켜 계 내에서 국지적인 고농도 상태를 유발하므로 안료의 응집과 고전단 하에서의 유동성을 악화시키는 것을 확인하였다. 또한 물분자를 흡수한 팽윤 구조체는 도공액의 탄성적 거동특성을 나타내었다. 반면 표면 흡착형 유동성 개량제(SAE)의 경우 물 분자를 불균일하게 분포시키지 않으며, 전하로 대전된 안료를 입체적으로 재분산하여 원지로의 침투특성을 개선함과 동시에 고농도 고속 도공시의 유동성을 개선함을 확인하였다. 도공액 농도가 상승됨에 따른 안료간의 자유이동 행로 단축과 마이그레이션(migration) 억제를 통해 라텍스(SB latex)의 투입량을 절감시킬 수 있었으며, 바인더 요구량이 낮은 중질탄산칼슘의 비율 확대도 이에 기여하였다. 라텍스 입자경의 미립화에 의해 고농도 도공시의 유동 특성의 장점을 확인하였으며, 중질탄산칼슘의 비율이 높은 도공액에서 유동특성의 장점은 더욱 확대되었다. 단 라텍스의 입자경이 지나치게 작고, 흡수용적인 큰 고평량 원지에서는 바인더의 비표면적 증가로 인한 pick strength의 증가현상이 나타나지 않고 바인더 마이그레이션의 심화로 인한 두께 방향에서 바인더 부재 영역이 존재하여 pick strength가 오히려 감소되는 것을 확인하였다. 고농도 도공시 건조특성이 향상됨에 따라서 도공량이 적은 저평량 원지 도공시 건조조건의 재조정 없이도 도공속도의 상승이 가능하였으며, 도공량이 많은 저속의 고평량 원지 위에 도공시에도 도공속도의 감속 없이 건조기의 온도를 낮출 수 있음을 확인하였다. This work describes the examination on the influence of control factors upon high solid coating. This study aimed for understanding what factors have to be considered and how those should be optimized for achieving successful high solid coating technology. The control factors examined in this research include coating formulation(pigment type, pigment ratio, binder level, solid content etc.), coating material performance(rheology modifier, SB latex), base paper properties, coating color properties and process variables. In lab-scale experiment, it was observed how coating formulation and coating material affects on coating rheology, penetration behavior and coating quality. With various coating formulation, the influence of base paper properties on coating properties was also studied. The effect of processing variables(coating speed and drying condition) was explored by the commercial-scale trial. High solid coating can improve the properties of coated paper, despite the reduction of clay in coating formulation. Coating formulation with GCC-rich pigment system brought out the increase in brightness of coated paper and also better light-fastness because optical brightener can be decreased in coating formulation. Conventional alkali swellable emulsion(ASE type rheology modifier) proved to be unsuitable for high-solid coating due to its bad rheological behavior under high shear condition, higher elasticity of coating color and poor coating color stability. Surface adsorption emulsion(SAE type rheology modifier), on the other hand, showed better rheological behavior and better coating color stability. It is concluded that the difference in coating performance between two kinds of coating additives(ASE, SAE) is originated from the difference in working mechanism. The swellable additives such as ASE, CMC, HEC and starch are thickened by absorbing water molecule exclusively and they can cause the local depletion of water in coating color system. Swollen matrix can contribute to higher elasticity of coating color and pigment agglomeration may happen in local high solid domain. On the contrary SAE type rheology modifiers do not constrain water molecule unlike swellable additives and also re-disperse electrostatically the dispersed pigment with steric-stabilization mechanism. High solid coating made it possible to reduce binder level in coating formulation without deterioration in picking strength. It can be explained that high solid coating system reduces binder migration and improves binding efficiency by shortened free-path length for binder mobilization. The SB latex with smaller particle showed the improvement in coating rheology under high shear condition. Its improvement in rheological behavior was more effective for GCC-rich coating formulation. In general, as particle size of SB latex reduced, the increase of binding force can be expected due to surface area broadening. However, the binding force of SB-latex with excessive smaller particle size strongly depends on sizing degree of base paper. It can be explained that the migration of SB latex can be affected by absorptivity of base paper. Keeping invariable moisture content of the coated paper, high solid coating increased coating speed without raising of temperature in dryers. And it also allowed the reduction of temperature in dryers without decreasing of coating speed.

高流動콘크리트의 流動特性 및 工學的 特性에 미치는 諸影響要因에 관한 硏究

김규용 忠南大學校 大學院 1999 국내박사

A distinctive different aspect from high flowing concrete and regular concrete is magnetic fillingability that high flowing concrete has differentiation in solidity of concrete state. Unlike fluidity evaluation data of regular concrete from slump, flowability, fillingability, spatial passability, material segregation resistance in high flowing concrete. To represent high flowing charateristics with engineering method, phisical evaluated data such as rheology integer are used. From this point of view, there are currently somewhat different opinions from one researcher to another. Therefore it needs continuative continuous and systematic evaluation and analysis on every characteristic according to its materials and mix rate. The using high flowing concrete expects to increase for construction of large building or for applying concrete under special circumstances. Accordingly, Carrying out a systematic research on causative aspects to the characteristics of high flowing concrete such as high flowability, durability, solidification characteristic is both background and necessity of this study. This paper consists of as follows In chapter 1, the necessity and goal of this study is described. In chapter 2, high flowing concrete is defined and most of speculation methods in evaluation of high flowing characteristic, and the research trends is described. In chapter 3, through the observation of paste according to the types of cement and high range water reducing AE agent in rheology, and evaluation of high flowing characteristic, the effect and compatibility of cement and high range water reducing AE agent is speculated. In chapter 4, as an experimental research in evalution and analysis of high flowing characteristics according to the types of fine·coarse aggregates and foundmental properties, fillingability and spatial passability according to the types of fine aggregates, fineness modulus, particle sharp and grading, the maximum of coarse aggregates are evaluated and the effect to aggregate as separator admixture within matrix analyzed. In chapter 5, an adequate mixture level is proposed on mixture factors of binder based high flowing concrete through speculating the range of flowing area of high flowing concrete according to level of W/B, the amount of water content, the amount of composition binder content as an experimental research on mixture factors of high flowing concrete. In chapter 6, the speculation and analysis on properties of heat of hydration, strength actuation characteristics and elasticity coefficient as well as durability characteristics on aridity and contraction characteristics, and freezing and melting resistance as a behaivour of long time is performed as en experimental research on strength actuation and durability of high flowing concrete. In chapter 7, The regulation on quality of high flowing concrete is proposed through comprehensively speculating the factors affecting the characteristics of high flowing concrete. In chapter 8, the overall conclusion and future study is mentioned. Conclusion 1 speculation of affection to high flowing concrete cement in accordance with quality and class of high range water reducing agent and cement 1) The research related to the state of cement paste in accordance with quality and class of high range water reducing agent high range water reducing agent and cement (1) From the perspective of gaining fluidity, HBC was shown superior in state with respect to the types of cement, and polycarbon acid based was shown superior in state with respect to the types of high range water reducing AE agent (2) The decrease of cement paste flow according to elased time was shown large in HBC with respect to the types of cement, and in polycarbon acid based with respect to the types of high range water reducing AE agent. (3) The outer viscosity in the range satisfying the goal flow 35±3cm of cement paste was shown in the order of OPC-FA30, OPC-FA0, HBC. (4) The correlation between the flow of cement paste and outer viscosity was shown relatively higher than other tendencies of high range water reducing AE agent. (5) Since the correlation coefficient about cement paste flow 23cm approach velocity, flow and rheology value was in good level, it can be thought of as an important evaluation method from the perspective of physical evaluation methods. 2 A experimental research on the engineering characteristic and fluidity of high flowing concrete in accordance with additives ratio in high range water reducing AE agent. (1) A care would be required since tendency of material segregation occurs if there is over 1.7% of additives ratio in high range water reducing AE agent. (2) As slump flow increases high by readdition of high range water reducing AE agent whenever it is needed not by making addition all at once, so readdition is recommended. (3) Compressive strength in accordance with the additives ratio in high range water reducing AE agent tends to be decreased as the addition ratio of high range water reducing AE agent increases. 3) A experimental research on the engineering characteristic and fluidity of high flowing concrete in accordance with the types of additives in high range water reducing AE agent. (1) H.B.C takes more advantages in concrete's flowability than O.P.C and flowability effect of high range water reducing AE agent was proved to have another state of compatibility, and material segergation resistance appeared to be better in most combinations except P type of O.P.C. (2) For setting time according to the types of high range water reducing AE agent, type P appearde to have faster setting state than type N that appeared to have delayed setting state by multitude addition. (6) For compressive strength, type P actuates higher compressive strength than type N. For the types of cements, H.P.C actuated lower than O.P.C in age of 1 week, but actuated analogously in age of 8 weeks. 2 Speculation and analysis of influence accroding to fine·coarse aggregate of high flowing concrete. 1) An experimental research on fluidity and engineering characteristics of high flowing concrete at substitutes ratio of Fly-ash according to the types of fine aggregate. (1) For gaining delaying time in flowability of high flowing concrete, as fineness modulus became smaller such as river sand, crused sand, and sea sand, the delaying time in high flowability became longer. (2) Most of flowability characteristics of high flowing concrete appeared to be better state in using river sand than crused sand, sea sand. 2) An experimental research on most of flowability characteristics of high flowing concrete according to fineness modulus of fine aggregate. (1) As fineness modulus of fine aggregate increases, flowability tends to increase. Furthermore, material segregation tendency was observed in case 3.43. (2) It is thought that fineness modulus of fine·coarse aggregate and aggregate's friction effect and bridge effect by grading state greatly affect concrete's flowability, spatial passability, fillingability, material resistance. 3) An experimental research on flowability and engineering characteristics of high flowing concrete according to the size of coarse aggregate and the ratio of fine aggregate. (1) In slump-flow, the last distance tends to decrease as the ratio of fineaggregate increases, which can be thought of due to the increase of viscosity according to the increase of space ratio of fine aggregate as it increases in its ratio. (2) In case of relatively large coarse aggregate, L-spatial slump, was low by an interference between aggregates such as friction and bridge effect on L-spatial passability, which consistancy and workability is expected to be lower. 3 An experimental research on mixture factors related with flowability of high flowing concrete. 1) An experimental research on evaluation of flowability and engineering characteristics of high flowing concrete according to substitute ratio of Fly-ash and the level of the amount of composition unit. (1) For spatial passability, while the increase of viscosity according to the increase of binder causes to lower the flowing velocity and fluidity of V-funnel, insufficiency may cause brocking state through aggregate's friction. So an adequate binder should be considered according to particle, grading of aggregate. (2) In variation of compressive strength according to the amount of composition unit and Fly-ash substitute ratio, the more the amount of composition unit increased the higher compressive strength was gained. 2) An speculation and analysis on factors of mixing design of high flowing concrete (1) Viscosity, fluidity and spatial passability was quite good in the level of 175, 185 ㎏/㎥ on W/B 0.30 and 0.35. So it can be thought of a good range when manufacturing high flowing concrete. (2) Since the range of compressive strength on age of 28 day is 300-900kgf/cm in every W/B, it can be feasible to manufacture high strength concrete. 4 An speculation on strength actuation and durability characteristics of high flowing concrete 1) An speculation and analysis on mechanical characteristics and properties of heat of hydration according to the types of cement of high flowing concrete. (1) heat evolution of amount according to the types of cement tends to be analogous between O.P.C and B.S.C. O.P.C-FA30 is somewhat low and after 5 hours later in H.B.C, state of heat of hydration was observed which is very low level of state of heat of hydration. In addition, state of heat of hydration of O.P.C and O.P.C-FA30 increased greatly after 8 hours later during 25 hours, but it was relatively low increase in B.S.C. (2) For the setting time according to the types of cement and the temperture variation, the setting and solidification of concrete became longer in 5℃. Accordingly, if the outer temperature is low, much care in curing temperature would be required when actuation and promotion of high flowing concrete. (3) Since base temperature of strength actuation differed according to the types of cement, base temperature in each composition ratio has to be calculated and then applied in order to get an accurate maturity. (4) In the amount of increase in temperature according to the elapsed time of the types of cement, O.P.C was 59℃ in mixture of binder content 500㎏/㎥. It was 12℃, 9℃ and 5℃ higher that O.P.C-FA30, H.B.C9℃ and B.S.C respectively. (5) The elasticity coefficient on level 300∼600kgf/㎠ of strength in high flowing concrete according to types of cement was shown in range of 2.5∼3.3×10^5kgf/㎠. 2) An experimental research on freezing and melting resistance of high flowing concrete according to whether or not the existence of AE agent and Fly-ash substitute ratio of W/B. (1) In combinations except W/B 0.30, the case with AE agent was appeared to be superior to the case without AE agent in durability of freezing and thawing apsect. 3) An experimental research on aridity and contraction characteristics of high flowing concrete according to the amount of unit and W/B. (1) The amount of aridity and contraction metamorphosis according to the amount of unit in the same W/B tends to increase as the unit increases. (2) Since metamorphosis 8.94×10 was shown after 24 weeks with W/B0.30, water content 185㎏/㎡, the maximum extent of aridity and contraction metamorphosis 8×10^-4 was passed which was proposed by 『建築工事標準仕樣書·同解說 JASS 5 鐵筋 コソク-ト工事』 in JCI. Therefore it is desirable to lower the amount of unit less than 175㎏/㎥ when manufacturing high flowing concrete. * Athises subimtted to the Committee of Graduate School, Chungnam National University on partial fulfillment of the requirements for the degree of Doctor of Engineering conferred in February 1999

點火에너지와 豫混合氣 流動特性이 電氣點火機關의 燃燒에 미치는 影響

이중순 동아대학교 1997 국내박사

희박혼합기를 유동분위기에서 급속하게 연소시켜 기관 구동시 발생할 수 있는 토크의 변동을 최소화하고, 유해한 배기가스의 배출량을 저감시키기 위한 기술의 개발이 필요하다. 즉, 희박연소의 실현을 위해서는 희박한 혼합기의 발화성 향상을 위한 점화조건 재선과 연소촉진을 위한 혼합기 유동조건의 개선이 요구된다. 따라서, 본 연구에서는 난류강도의 제어가 가능한 유동형 정적연소기와 단기통 가시화기관 및 실기관을 사용하여 연구를 수행하였다. 혼합기의 유동특성과 점화에너지 방전특성이 연소에 미치는 영향을 밝히기 위하여 방전횟수 및 기간의 제어를 통해 점화에너지 방출 패턴을 변화시킬 수 있는 고주파점화장치(high frequency ignition system)를 개발하였다. 이를 통하여 점화조건과 점화핵(jgnition kernel) 성장의 관계 및 유동특성과 점화에너지의 방전특성이 전기점화기관의 연소에 미치는 영향을 실험적으로 고찰하여 착화와 연소를 고려한 기관 내에서의 적정 유동조건의 규명과 함께 유동 및 당량비를 고려한 적절한 점화방법을 제시하였다. 희박연소 기술 개선 및 저연비 연소실 설계를 목적으로 실린더 내의 혼합기 유동과 점화에너지 방전특성이 예혼합기의 연소에 미치는 영향에 대한 실험적 연구를 수행한 결과를 요약하면 다음과 같다. 1. 착화성은 점화에너지의 밀도가 높은 경우에 양호하나, 점화에너지 밀도는 낮아도 방전시 용량성과 유도성에너지가 다수회 발생하는 고주파정화의 경우에 더욱 양호하다. 2. 고주파점화장치의 방전특성이 혼합기의 착화 및 실기관의 운전특성에 미치는 영향은 1차전압, 방전기간, 방전주파수의 순으로 나타났다. 3. 난류강도의 증가와 함께 열이용효율이 증가하는 현상은 난류강도의 증가로 인한 연소기간이 단축되는 영향인 것으로 판단되며, 희박혼합비 영역에서 높은 열이용효율을 보이는 것은 희박혼합비에서 연소최고온도가 낮기 때문이다. 4. 고주파점화장치를 사용한 경우에 희박한 혼합비 영역에서도 도시평균유효압력의 사이클 변동률은 5% 이하로 낮게 나타나는데, 이는 방전시 용량성과 유도성에너지가 다수회 발생함으로써 초기화염 형성에 기여하기 때문인 것으로 판단된다. 5. 순수 텀블유동에 비하여 텀블비와 스월비의 크기가 상대적으로 적절한 값으로 존재하는 경사 텀블유동의 경우가 화염전파를 촉진하였다. 6. 고주파점화장치는 혼합기의 유동특성에 따라 서로 다른 스파크방전 형성기간과 방전기간 및 1차전류 회복기간을 보였다. 7. 압축말기의 연소실내 유동특성은 화염전파속도에 영향을 미치고, 순수 텀블유동에 비하여 스월이 가미된 경사 텀블유동의 경우에 화염의 중심분포도가 집중되는데, 이는 설정된 유동조건이 화염의 전파에 유리한 영향을 주어 연소 안정성이 개선된 결과로 보인다. For the improving fuel economy and the reducing exhaust emissions in spark-ignition engines, the concept of lean burn is a concurrent attractive feature. Ignition instability and the reduction of flame propagation rate result in the increased cycle-to-circle combustion variations associated with lean burn. Combustion stability under lean mixture conditions could be improved by increasing burning rates through enhanced flow characteristics and by securing ignitability with better ignition systems. High-frequency ignition system(HIS) was developed to improve the stability of initial flame development under the lean burn condition. The electrical principle of the HIS is based on successive spark discharges in a spark plug. The ignition system provides electronically controlled charges in spark duration(1∼10msec) and restriking rates(5∼30kHz). Flow characteristics of tumble-swirl were varied with swirl control valve(SCV) attached to the combination of tumble and swirl strengths achieved by various shapes of SCV. The effects of flow and ignition characteristics on the combustion performances and their interaction were investigated in a constant volume combustion chamber and a 4-valve SI engine. Flow characteristics were quantified by steady flow tests and in-cylinder flow measurements. Ignition energy and its distribution were measured through secondary voltage and current measurements, and controlled in a HIS by changing spark duration and sparking frequency. Combustion performances were evaluated by pressure analyses, exhaust gas analyses and the photographs analyses of initial flame propagation taken by a schlieren optics and an ICED camera in a constant volume combustion chamber and a single-cylinder optical engine. The improving of lean burn performances by the optimum flow and ignition characteristics was discussed. The results of this study are summarized as follows ; 1. The increase of ignition energy has a positive effect on that of the maximum combustion pressure, as the mixture gets leaner within the lean agitability limit. 2. The absolute value of ignition energy and its distribution of ignition systems have a great influence on the operating characteristics of engine, as the mixture gets leaner within the lean agitability limit. 3. A HIS developed to improve lean bum has a resonant frequency range of 15∼25khz where the breakdown voltages are highest. 4. Longer spark durations, over the 1.5msec, retain the successful ignition for very lean mixtures up to A/F 23 and longer duration expands lean ignition limit. 5. Optimum ignition requirements are determined by the flow characteristics. Discharge patterns, which is characterized by spark duration and frequency, and ignition energy influences the engine stability especially under lean mixture conditions. In this study, 2msec spark duration, 20khz discharge frequency and 120v primary voltage give the best performance of HIS on the consideration of regular driving condition. 6. HIS enables ignition to be made successfully even in the strong flow field such as inclined tumble/swirl because the supply of successive ignition energies induces increase of kernel volume and enhances the flame propagation speed of the early flames.

가솔린機關의 燃燒室 形狀과 流動特性이 燃燒 및 排氣가스 排出에 미치는 影響에 관한 硏究

김대열 國民大學校 自動車工學專門大學院 2004 국내박사

최근 에너지 자원의 고갈 및 환경오염문제가 크게 대두됨에 따라 자동차 기관 개발에 있어서 성능위주의 기관 개발에서 연비향상과 유해배기가스 저감에 대한 연구로 집중되고 있다. 주어진 연소실에서 공기와 연료의 혼합과 연소에 가장 큰 영향을 미치는 것은 난류와 스월 유동과 같은 실린더 내의 유동이다. 이와 같이 연소실 내 유동은 연소 및 배출가스 특성에 매우 중요한 변수 중의 하나이다. 그러나 현재 국내의 경우에는 희박연소기관 개발을 통해서 연소의 안정화를 꾀하고 있는 실정이어서 가솔린 이론 공연비를 유지시키면서 PDA 밸브에 의해 난류유동강화를 촉진시켜 연소의 안정화를 구하는 연구는 미흡한 실정이다. 따라서 본 논문에서의 연소실 형상에 의한, PDA 밸브장착에 따른, 그리고 점화플러그 위치 변동에 의한 연소특성 및 배출가스 특성에 관한 연구를 수행하였다. 연소의 안정화에 대한 연구를 하기위하여 흡기포트형상 및 연소실 형상을 설계하였으며 정상유동 실험장치를 이용하여 PDA 밸브 장착과 미장착에 따른 유량특성, 스월비 및 텀블비 등에 관한 연구를 수행하였다. 최적 연소실 형상에 대한 연구결과, 연소실 유동 상태를 난류모델의 개발에 따른 수치해석적 방법을 통하여 난류모델의 수치결과치와 정상유동장치 실험결과와 비교함으로서 결과적으로 CFD 프로그램의 타당성을 검증하였다. 또한 PDA 밸브를 이용한 사이클 변동실험과 점화플러그 위치변동실험 등을 통해서 연소의 안정화를 구하기 위해 연소 및 배기가스 특성에 대하여 연구하였다. 이와 같은 결과, 연소의 안정화 측면과 연비측면에서는 스월 강화를 위해 연소실 바깥라운드 반경을 10mm로 만든 연소실이 가장 사이클 변동이 적은 연소실임을 알 수 있었고, PDA 밸브 적용시 적용하지 않는 경우보다 연소가 더 안정화됨에 따라 연비 향상은 있었지만, 배출가스 중 HC, NO_(x)는 오히려 더 배출되었다. 그리고 점화플러그 위치 변동 실험결과, 공기유도특성을 나타내는 공기 유량계수(Cf)값은 모든 연소실에 거의 유사한 값을 나타내었고, PDA 밸브 적용시 스월비 및 텀블비가 증가됨을 알 수 있었다. 또한 유동실험 결과와 예측한 결과들과 일치함을 알 수 있었다. Recently, as our precious planet has gradually faced so serious critical problems such as air pollution and the lack of energy resources that many creative researchers have changed their study focus from upon how to develope the engine efficiencies to upon how to reduce the harmful exhaust emission of Automobile and enhancement of fuel consumption rate. In a given chamber, the very factor that affects the mixture of air and fuel and, further, combustion, is nothing but such flow in the cylinder as turbulence and swirl flow. As such, the flow of combustion chamber is one of the most important variables in the characteristics of combustion and exhaust emission. However, in the cases of domestic studies currently being performed, the combustion is stabilized by way of the development of lean burn engine. Thus, it is demanded that the domestic studies have to focus more on making combustion stabilized by way of the reinforcement of the turbulent flow with the PDA valve, while air/fuel ratio is being maintained at the same time. This thesis studies on characteristics of combustion as well as exhaust gas which are directly influenced by 3 factors, that is, the formation of combustion chamber, the PDA valve and the change of an ignition plug location. To implement investigations on the stabilization of combustion, the study designs the forms of the intake port and combustion chamber. And it further performs research pertaining to the characteristics of flow flux, swirl and tumble ratios, etc, using experimental devices of steady flow. According to the research result from the formation of optimal combustion chamber, CFD (Computational Fluid Dynamics) program has been verified by comparing numerical result data and experimental result data of steady flow devices on the basis of numerical-interpretive method which accompanies the development of turbulence models in the fluid state of combustion chamber. According to the research on the characteristics of combustion and exhaust emission, this study confirms how to stabilize combustion by way of performing the experiments of cycle fluctuation and changes of a spark plug location. As a result from the study on combustion stability and fuel consumption, the study identifies the optimal combustion chamber, that is, having the least cycle change, as one that has 10mm radius for the outer round of combustion chamber in order to intensify swirling. And the improvement of fuel consumption is also verified, when the PDA valve is applied, because of the increased combustion stability On the other hand, HC and NO_(x) in exhaust gas are increased by the combustion of the application of PDA valve. Finally, as a result from the change of spark-plug position, air flux coefficient(Cf) in overall chambers shows similar results. Thus, it confirms that the swirl and tumble ratios are increased by application of the PDA valve. Also, it shows that the flow test results are consistent with expected results.

MPI 가솔린機關의 燃料噴霧 및 吸入流動特性이 燃燒性能에 미치는 影響

서영호 한양대학교 대학원 1997 국내박사

플레넘 챔버내의 유동 특성에 관한 실험적 연구

김윤희 한양대학교 대학원 1997 국내석사

정량적 예측 기반 콘크리트 펌프압송 성능 설계

장경필 명지대학교 대학원 2018 국내박사

최근 콘크리트 펌프압송 성능의 정량적 예측이 가능한 기술이 개발되어 실제 시공 현장에도 일부 적용되고 있다. 펌프압송 성능의 정량적 예측이 가능하다는 것은 설계가 가능하다는 것을 의미한다. 이 논문에서는 콘크리트 펌프압송 성능의 정량적 예측을 기반으로 한 설계 방법을 제안하였다. 콘크리트의 펌프압송 설계를 위해서는 배관 내 유동 메커니즘, 콘크리트와 윤활층의 유동특성 평가, 펌프압송 성능 예측, 펌프압송 중 콘크리트의 유동특성 변화 등 펌프압송과 관련된 여러 가지 인자 및 요소기술들이 필요하다. 이들 중 일부는 이미 개발되어 있거나 지속적으로 개선되고 있는 상태이다. 이 논문에서는 이미 개발되어 있는 요소기술들 중 개선이 필요한 사항과 부재한 요소기술들은 새로운 연구를 통해 확보하였으며, 이들을 통합하여 설계 방법을 제안하였다. 이 논문에서 제안한 펌프압송 설계 과정을 요약하면 다음과 같다. ① 펌프압송 조건 파악 : 대상 구조물의 길이 또는 높이, 공정관리를 위한 목표 토출량, 콘크리트의 배합강도 또는 설계기준강도 ② 콘크리트와 윤활층의 점도 관계를 이용한 압송압력 예측 ③ 압송 조건을 만족하는 콘크리트와 윤활층의 점도 범위 산정 ④ 설계기준강도와 ③에서 산정된 점도를 고려한 콘크리트 배합설계 ⑤ 설계된 배합에 대한 콘크리트와 윤활층의 유동특성 측정 ⑥ 유동특성 측정 결과를 이용한 압송압력 예측 ⑦ 펌프압송 조건 만족여부 확인 ⑧ 배합 선정 또는 배합 조절을 통해 ④에서 ⑦과정 반복 ⑨ 펌프 및 배관 치수 선정 ⑩ 펌프 실린더의 충진율 검토를 통한 현장 펌프운영 관리기준 설정 ⑪ 슬럼프 플로우 실험을 통한 현장 콘크리트 펌프압송 성능 품질관리 기준 설정 위의 설계 과정을 완성하기 위해 이 연구에서 새롭게 확보한 요소기술들은 다음과 같다. ① 펌프압송 성능 예측을 위한 새로운 윤활층의 유동특성 평가 방법 제안 ② 콘크리트와 윤활층의 유동특성 평가 방법에 따른 펌프압송 성능 예측 정확도 평가 ③ 펌프압송 중 콘크리트의 유동특성 변화 분석 ④ 현장 펌프운영 관리기준 제시를 위한 콘크리트 펌프 실린더의 충진율 모델 개발 ⑤ 혼화재료 사용을 통한 콘크리트의 펌프압송 성능 조절 ⑥ 콘크리트와 윤활층의 점도 관계 분석 ⑦ 콘크리트의 펌프압송 성능 품질관리 기준 제시를 위한 T500-콘크리트 점도 관계 제안 이 논문에서 제안한 펌프압송 설계 방법의 검토를 위해 세 가지 경우에 대해 펌프압송 설계를 수행하였다. 첫 번째는 초고층 빌딩을 고려한 500 m 높이 수직펌프압송 설계, 두 번째는 장거리터널 및 초장대 교량을 고려한 1,000 m 수평펌프압송 설계, 세 번째는 최근 많이 건설되고 있는 200 m 높이 건물에 대한 수직펌프압송 설계를 수행하였다. 콘크리트 펌프압송 성능의 정량적 예측을 기반으로 목표 토출량을 만족하는 여러 가지 콘크리트 배합을 고려할 수 있었으며, 이에 따라 펌프 및 배관 치수를 선택할 수 있어 경제성을 고려한 설계가 가능하였다. Recently, a technique of quantitative prediction of the concrete pumping performance has been developed and applied to real construction sites. The possibility of quantitative prediction of concrete pumping performance means the design is practicable. The purpose of this paper is to propose a design method of concrete pumping performance based on quantitative prediction. For the design of concrete pumping, various factors related to concrete pumping such as the flow mechanism of the concrete in pipe, prediction of pumping performance, evaluation of rheological properties of concrete and slip layer, and variation of rheological property of concrete during pumping are required. Some of these have already been developed or are undergoing continuous improvement. In this paper, the technologies that need improvement and the absent have been acquired through new researches, and the design method has been completed by integrating them. The design process of concrete pumping proposed in this paper is summarized as follows. ① Understanding pumping conditions : Length or height of target structure, target discharge rate for process control, design strength of concrete ② Prediction of required pressure using the viscosity relationship of concrete and slip layer ③ Determination of viscosity range of concrete and slip layer satisfying pumping condition ④ Concrete mix design considering the design strength of concrete and the viscosity determinated in step ③ ⑤ Evaluation of rheological properties of concrete and slip layer for the mix designed concrete in step ④ ⑥ Prediction of pumping pressure using measurement results of rheological property ⑦ Confirmation of satisfaction of pumping condition ⑧ Selecting the concrete mix or repeat steps ④ to ⑦ by adjusting the mix proportion ⑨ Determination of pump and pipe size ⑩ Establishment of the operating management standard of the concrete pump at on-site by reviewing filling coefficient of the pump cylinder ⑪ Establishment of quality control standard for on-site concrete pumping performance through the slump flow test In order to complete the above design process, the newly acquired technologies in the study are as follows. ① Suggestion on new method of measuring the rheological property of slip layer ② Evaluation on prediction accuracy of pumping performance according to measurement methods of rheological properties of concrete and slip layer ③ Analysis on variation of rheological property of concrete during pumping ④ Development on filling coefficient model of pump cylinder to establish the operating management standard of concrete pump at on-site ⑤ Control of pumping performance by using mineral and chemical admixture ⑥ Analysis on the viscosity relationship of concrete and slip layer ⑦ Suggestion on the T500-concrete viscosity relationship for quality control standard of pumping performance at on-site In order to investigate the proposed design method, the design of concrete pumping was performed for three cases. The first is the design of vertical pumping for 500 m height considering the high-rise building. The second is the design of horizontal pumping for 1,000 m distance considering the long-distance tunnel and bridge. The third is the design of vertical pumping for 200 m height building to build a lot recently. Based on quantitative prediction of concrete pumping performance, it was possible to consider various mix proportions satisfying the target flow rate. In addition, since pump and pipe dimension can be selected, economical design was possible.

유동층 환원로내에서 분철광석의 유동특성 및 분화거동에 관한 연구

정우창 부산대학교 대학원 1998 국내박사

- Characteristics of a cold fluidization - In this study, a cold fluidized-bed for sinterfeed of wide size range 1∼5 mm has been comprehensively characterized in terms of minimum fluidization velocity, fluidized-bed regime, variation in pressure drop, degradation and holdup of axial direction using manometers and differential pressure transmitters(DPTs). In the experiment, a acryl tube was employed as a cold reactor and nitrogen and reducing gas, which was synthesized to have similar composition to a coal-gasified gas, were used as gas media. The range of superficial gas velocity in the reactor was 0∼3.5 Nm/s. The measured values of minimum fluidization velocity were compared with those calculated from the equation proposed by Wen & Yu and fairly good agreement was obtained. From the measurement of pressure drop(△P) in the reactor using seven DPTs installed along the vertical length of reactor, it was found that the degradation of iron ore is almost in the early stage of fluidization, within 5 minutes. In addition, the superficial gas velocity required for a optimal bubbling fluidization is 1.2∼1.4 times minimum fluidization velocity and the solid holdup in the bubbling fluidized-bed ranged 0.2~0.3 depending on the particle size and size distribution. The amount and size distribution in each section between DPTs can be predicted from the measurements of △P. Calculating the solid holdup in the bed from the measurements, the variation in the bed height with ore weight can be also predicted. The results from the present study could be used as basic data for hot fluidized-bed. -Characteristics of a hot fluidization - Characteristics of a fluidized bed with iron ore fines in the size range of 1 to 5mm have been investigated at high temperature (700∼850℃) in terms of the minimum fluidization velocity, fluidization patterns, the pressure drop, the solid hold-up in the reactor, etc. using a laboratory scale fluidized bed reactor. It was observed that the minimum fluidization velocity of particles in wide size range is equivalent to that of the particle of harmonic mean size. The measured values of minimum fluidization velocity were compared with those calculated from the equation proposed by Wen & Yu, Richardson and Grace fairly good agreements were obtained. The minimum fluidization velocity for fine ore particles smaller than 1500㎛, of which fluidization behavior is governed by the viscosity of gas, decreases with a increase in temperature while that for coarse ore particles larger than 1500㎛, of which fluidization behavior is governed by the force of inertia, increases with temperature. In addition, the optimum gas velocity for fluidization is about 1.25 times of the minimum fluidization velocity and this is similar to the result observed in the minimum fluidization velocity and this is similar to the result observed in the experiments in a cold state. During heat-up and reduction in the reactor, iron ore particles are degraded due to the thermal shock and reduction reaction. It was also fond that the degradation of ore particles was completed in the early stage of reduction reactions. - Degradation behaviors of iron ore fines - Three mechanisms of the degradation behavior of iron ore fines(IOF) sized 1 mm to 5 mm during fluidized-bed reduction have been investigated: mechanical degradation(MD), thermal degradation(TD) and reductional degradation(RD). The effects of operational parameters such as ore type, temperature, superficial gas velocity, and reducing gas composition have also been studied. The degradation in three mechanisms has been quantitatively evaluated by the amount of IOF smaller than 1mm which was produced and by the weight change of IOF in the bed during fluidization. The reductional degradation become the most predominant aspect among the three and the thermal degradation is the least when the IOF has a low water content, while the degradations of all three aspects are not much different in contribution when the IOF has a high water content. For the effect of operating parameters, the IOF of a lower sphericity showed a higher degradation in the cold fluidization under inert atmosphere but this effect was lessened or negligible under a fluidized-bed reduction at a high temperature. A higher water content in the IOF demonstrated a higher degradation at a high temperature. In the fluidized-bed reduction, the degradation was little affected by the reaction temperature, the superficial gas velocity, and the reducing gas composition. In addition, all three aspects of degradation were mostly completed in the early stage, within 15 minutes, of the reduction reaction. - Elutriation characteristics of iron ore fines - The reduction behavior of iron ore fines of multi-sized distribution in a fluidized-bed has been extensively investigated in the aspects of degradation and elutriation. The present study has endeavored to obtain fundamental data for effective plant operations and improvements of devices in fluidized-bed systems through fully understanding the effects of operating parameters and dimension or design of reactor on the degradation and elutriation of ore fines during the fluidized-bed reduction. The abrasion and degradation during fluidized-bed reduction are more severe when the ore particles are coarse, and in this study, the weight percent of ore particles smaller than 250㎛ increased from 27wt% to 45wt% and that of ore paricles smaller than 500㎛ increased from 42wt% to 57wt% after the fluidized-bed reduction. It has been confirmed with a mathematical model of elutriation loss that as the superficial gas velocity increases, the fluidization of coarse ore becomes more vigorous but the elutriation rate and concentration of iron ore fines entrained in gas also increase and it finally results on a high elutriation loss. These results could be used as basic data for interpretating the reduction behavior of fine iron ore of wide size range. The present study is also expected to provide useful parameters critical in the determination of reactor size in a scale-up of a fluidized-bed system.

유동특성 개선을 위한 C형 스트레이너 설계ㆍ제작 및 성능시험에 관한 실험적 연구 : Y형 스트레이너와 비교를 중심으로

신병균 한세대학교 2017 국내박사

Strainers are used to remove foreign matter from pipes in construction and industrial facilities. Installed at the front tips of valves, machines and pumps of all kinds, they block the inflow of foreign matter and play critical roles to ensure the safe operation and long life of internal engines. This study set out to design a new C-type strainer, which would improve old strainers with their installation problems and the inconvenience of eliminating foreign matter piled up in the current screen, undergo no flow path changes, and have a small flow loss due to fluid resistance. It also aimed to test the superior fluidity of the strainer with an experiment. The new C-type strainer was designed in a structure suffering small flow losses thanks to lower fluid resistance via the screen, having fewer limitations with the installation space when pipes were installed on the floor of construction site, and removing foreign matter with ease. Installed in pipes, strainers protect the flow system but work as a factor of pressure drops in hydrodynamic terms. Their bodies should thus be designed to filter foreign matter up to the design standard and cause fewer pressure drops in case of foreign matter pileup in the screen. The fluidity of strainers is presented in capacity coefficient (Kv), and the behavior of flow characteristics can be predicted with a simulator experiment or computational fluid dynamic (CFD) flow interpretation. The investigator conducted a comparative experiment with the Y-type strainer, which is most widely used in installation sites, and an actual-size 50A C-type strainer newly designed in a study at the flow laboratory of the Korea Research Institute of Standards and Science(KRISS) under four situations with no screen inside the strainer and with 0%, 15%, and 30% pileup of foreign matter. The results led to the following conclusions: 1. The experiment results in case of no screen inside the strainer (without a screen) show that the C-type strainer recorded a capacity coefficient that was 74.9% (157.2/89.9) higher than the Y type and a resistance coefficient that was three times (1.24/0.41) lower than the Y type, which indicates that the flow path shape and change (changing flow direction) of the main body had much influence on its capacity and resistance coefficient. 2. When there was 0% pileup of foreign matter in the screen inside the strainer, the C type recorded a capacity coefficient that was 54.5% (81.6/52.8) higher than the Y type and a resistance coefficient that was 2.4 times (3.57/1.50) lower than the Y type, which demonstrates that the C type had superior fluidity and that the screen inside the strainer was a hydrodynamic resistor. 3. When there was a 15% pileup of foreign matter in the screen inside the strainer, the C type recorded a capacity coefficient that was 54.2% (73.7/47.8) higher than the Y type and a resistance coefficient that was 2.4 times (4.38/1.84) lower than the Y type, which tells that the pileup of foreign matter in the screen of strainers will lead to differential pressure due to fluid resistance and decreased flux. 4. When there was a 30% pileup of foreign matter in the screen inside the strainer, the C type recorded a capacity coefficient that was 52.8% (68.3/44.8) higher than the Y type and a resistance coefficient that was 2.3 times (4.97/2.14) lower than the Y type, which indicates that the Y type suffered more pressure loss than the C type. In short, the findings demonstrate that the capacity coefficient of a strainer, which indicates its fluidity, was under the influence of flow path shape and change of the main body and the pileup size of foreign matter in the screen and that the C-type strainer recorded a capacity coefficient (Kv) that was over 50% higher than the old Y type and accordingly proved its superior hydrodynamic performance. 스트레이너는 건축․산업설비 배관에서 불순물 제거를 목적으로 사용되고 있으며 각종 밸브, 기기, 펌프 등의 전단에 설치되어 불순물 유입을 막고 내부기관의 안전운전과 수명을 보장하는데 중요한 역할을 하는 장치이다. 본 연구의 목적은 스트레이너의 설치상 문제점과 사용중 여과망에 불순물이 쌓였을 때 불순물을 제거하는데 불편한 점들을 개선하고 유로 변형이 없으며 유체저항에 의한 유동손실이 적은 새로운 형태의 C형 스트레이너를 설계․제작하여 기존 Y형 스트레이너와 비교실험을 통해 유동성의 우수함을 검증하는데 있다. 새로 고안된 C형 스트레이너는 여과망에 의한 유체저항을 적게 받아 유동손실이 적을 뿐만 아니라 설비 현장에서 바닥으로 배관을 시공할 경우에도 설치공간의 제약을 적게 받고 불순물 제거가 쉬운 구조로 되어있다. 배관에 설치되는 스트레이너는 유동시스템을 보호 하지만 유체역학적으로는 압력강하를 일으키는 요인으로 작용한다. 그러므로 스트레이너를 설계할 때는 불순물을 설계 기준치까지 거르면서 불순물이 여과망에 쌓였을 때 압력강하를 적게 일으키는 구조로 본체를 설계하여야 한다. 스트레이너의 유동성은 용량계수(Kv) 값으로 표시하며 유동특성에 관한 거동은 실물실험이나 전산유체역학적(CFD) 유동해석으로 예측할 수 있다. 본 연구는 설비현장에서 가장 널리 사용되고 있는 Y형 스트레이너와 새로 고안 설계․제작된 C형 스트레이너 50A 실물의 비교실험으로 성능시험을 하였다. 그 실험은 한국표준과학연구원(KRISS) 유량실험실에서 스트레이너 내에 여과망이 없을 경우와 불순물이 0%, 15%, 30% 쌓였을 경우 등 4가지 상황별 비교 실험을 통하여 다음과 같은 결과를 도출하였다. 첫째, 스트레이너 내에 여과망이 없을 때(without 여과망)의 실험결과 C형의 용량계수가 Y형보다 74.9%(157.2/89.9) 높았고, 저항계수는 오히려 Y형이 3배(1.24/0.41) 높아 본체의 유로형상과 유로변형(흐름방향 바뀜)이 용량계수와 저항계수에 많은 영향을 주고 있는 것으로 나타났다. 둘째, 스트레이너 내 여과망에 불순물이 0% 쌓였을 때에도 C형의 용량계수가 Y형보다 54.5%(81.6/52.8) 높았고, Y형의 저항계수가 2.4배(3.57/1.50) 높아 C형의 유동성이 우수하였으며 스트레이너의 여과망은 유체역학적으로 저항체임이 확인되었다. 셋째, 스트레이너 내 여과망에 불순물이 15% 쌓였을 때에도 C형이 Y형보다 용량계수가 54.2%(73.7/47.8) 높았고, Y형의 저항계수가 2.4배(4.38/1.84)로 높아 스트레이너의 여과망에 불순물이 쌓이면 유체저항을 받아 차압이 발생하고 유량이 감소한다는 사실을 알 수 있었다. 넷째, 스트레이너 내 여과망에 불순물이 30% 쌓였을 때에도 C형의 용량계수가 Y형보다 52.8%(68.3/44.8) 높았고, Y형의 저항계수가 C형보다 2.3배(4.97/2.14) 높아 Y형의 압력손실이 더 많다는 결과를 얻었다. 결론적으로 스트레이너의 유동성을 나타내는 용량계수 결정은 본체 유로형상, 유로변형, 여과망에 불순물 쌓인량에 영향 받았으며, C형으로 설계한 스트레이너가 기존 Y형 보다 50% 이상 용량계수(Kv)가 높아 유동성이 우수한 것으로 검증되었다. C형 스트레이너를 향후 건축․산업설비 현장에 적용할 경우 유체 기계의 안전운전 보장과 배관효율을 높여 유동손실을 최소화 시킬 것으로 판단된다.

다기능 포러스콘크리트의 혼합 및 진동방법에 따른 결합재의 유동특성과 현장적용성 평가에 관한 실험적 연구

金正煥 忠南大學校 大學院 2005 국내박사

우리나라는 고도의 산업화와 공업화 과정을 거치면서 삶의 풍요로움을 누려왔으나 반면에 자연환경 훼손과 무절제한 부존자원의 활용으로 자원의 고갈현상을 초래하고 있으며, 환경에 대한 인식보다는 경제논리에 입각하여 개발이 추진되어 이로 인한 개발지역 주변의 오염이 심각하게 되어 생태계 파괴를 일으키게 되었다. 건설 분야에서도 도시개발 시 환경문제의 해결 및 경관의 향상을 전제로 한 개발이 진행되어 콘크리트에 잔골재를 사용하지 않고 단입도의 굵은골재를 사용하여 인위적으로 연속공극을 형성시켜 투수성, 투기성, 흡음성, 수질정화 및 식생능력 등의 다기능을 가진 포러스콘크리트에 주목하여 전 세계적으로 연구가 진행되고 있으며 우리나라도 이에 관한 연구가 점점 증가하고 있는 추세에 있다. 따라서 본 연구는 포러스콘크리트의 성능향상과 품질의 안정화에 필요한 기초기술을 체계적으로 확립하고자 포러스콘크리트의 제조 시 결합재의 굳지않은 성질부터 성형성·경화체의 성능까지를 일련의 과정을 분석·검토하여 포러스콘크리트의 강도특성을 지배하는 요인을 확인하였으며, 실리카흄과 탄소섬유를 혼입한 포러스콘크리트의 특성을 분석하여 성능향상에 필요한 최적조건을 제안하였다. 또한 포러스콘크리트를 식생 및 수질정화용으로 사용하기 위한 현장적용성평가를 실시하였다. 본 연구에서 수행한 연구결과를 요약하면 다음과 같다. (1) 포러스콘크리트에 주로 사용되는 20∼25%의 낮은 물-시멘트비 영역에서의 결합재의 유동성은 물-시멘트비가 커질수록 증가하였고, 혼합시간이 경과할수록 안정화되었으며, 옴니믹서로 혼합한 경우가 강제식 믹서로 혼합한 경우보다 양호한 유동특성과 강도특성을 나타내어 혼합기구와 성능이 결합재의 유동특성과 강도특성에 영향을 미치는 주요한 요소인 것을 확인하였다. (2) 옴니믹서의 성능에 따른 결합재의 유동성과 레올로지 특성은 혼합시간 270초 이상, 회전수 200rpm에서 안정화되며, 고성능AE감수제의 첨가는 포러스 콘크리트에서 사용되는 물-시멘트비 영역에서 효과적인 것으로 나타났다. (3) 5∼13mm 골재를 사용한 포러스콘크리트는 다짐에너지 100 kN·m/㎡을 가하고, 설계공극률 15, 20, 25%에 대하여 흐름값이 각각 150, 200, 250%일 때 시멘트 페이스트의 흘러내림이 발생하지 않고 양호한 강도특성을 나타내었고, 13∼20mm 골재를 사용한 포러스콘크리트는 설계공극률이 20%인 경우 다짐에너지 50 kN·m/㎡, 흐름값 200%에서 가장 양호한 강도특성을 나타내었다. 따라서 최적의 포러스콘크리트를 제조하기 위해서는 골재입도와 설계공극률에 따라 적절한 다짐에너지와 시멘트 페이스트의 유동성을 확보하는 것이 중요하다고 판단된다. (4) 실리카흄과 탄소섬유를 혼입한 포러스콘크리트는 실리카흄과 탄소섬유의 혼입률이 증가함에 따라 공극률과 투수계수는 감소하였고, 실리카흄을 10% 혼입한 경우와 탄소섬유를 3% 혼입한 경우가 가장 양호한 강도특성을 발현하였다. 또한 실리카흄 10%와 PAN계 탄소섬유 3%를 혼입한 포러스콘크리트는 보통포러스콘크리트 보다 22.4배의 등가휨강도를 발현하여 변형성능이 현저히 개선됨을 확인하였다. (5) 포러스콘크리트에 호밀풀과 낭아초를 식재하여 식생능력을 평가한 결과, 파종 후 30일까지는 객토층에 존재하는 양분과 수분을 공급받아 양호한 생육상태를 나타내었으나, 파종 후 60일 후부터는 골재입경과 공극률이 작을수록 생육상태는 부진하였다. 따라서 포러스콘크리트의 식생능력은 골재입경에 의한 영향을 가장 크게 받으며 동일한 골재입경에서는 공극률에 영향을 받는다고 판단된다. (6) 포러스콘크리트를 하천에 침지시켜 미생물을 부착시킨 후 실내수질정화수로에서 수질정화 능력을 평가한 결과, 포러스콘크리트는 골재입경이 작을수록 또한 동일한 골재입경에서는 설계공극률이 클수록 인과 질소의 제거능력이 향상되었다. 따라서 포러스콘크리트의 수질정화 능력은 연속공극으로 형성된 비표면적의 크기에 큰 영향을 받는다고 판단된다.