Demonstration Testing of Boiler Tubes in a Clean Power Test-Bed Plant

Yeon kwan Kang,Yinsheng He,이한상,김범수,Liming Xu,신기삼 대한금속·재료학회 2019 대한금속·재료학회지 Vol.57 No.12

The use of locally developed high performance alloys in power plants has become essential in the past ten years. Application of these alloys has been difficult because of a shortage of field demonstration testing, and the lack of lab-based test data. In this work, three types of locally developed heat resistant alloys were demonstration tested in boiler tubes in a power plant. The test procedures included a pre-test, a field demonstration and a post-test. The pre-test revealed the quality of the local tubes was the same level as the originally imported tubes. This suggested the potential outcomes of further demonstration testing. The demonstration was carried out by replacing parts of the original components with newly manufactured test components, made of local and imported tubes. There were no failures in the test components after 13,000h of operation. A portion of the tubes were sampled for a post-test, while the remaining parts were operated in the boiler for an even longer time. The post-test results revealed no significant degradation of the properties of the local tubes. The works no matter set up the properties database, but also set-up the performance and reliability, as well as test procedures for locally developed tubes.

수열원 열펌프시스템용 적산열량계의 냉방, 난방 성능특성에 관한 연구

강희정,이현수 한국기계기술학회 2019 한국기계기술학회지 Vol.21 No.2

In this study, the cooling and heating amount, temperature, flow rate of turbine type heat meter for water source heat-pump system were experimentally investigated at the standard operating conditions. The obtained cooling and heating capacity from the heat meter were deviated within 5.0%, 3.8% comparing with the precise values calculated from an accredited test facility. Even though the accumulated cooling and heating amount values of the heat meter had a small difference comparing with the precise values, the temperatures of heat meter showed greatly different values comparing with the precise temperature. Therefore, it is highly recommended to develop the heat meter which is appropriate for the water source heat pump systems.

Performance investigation of a novel calorimeter for a heat pump system according to flow loops

Kofi Owura Amoabeng,이광호,JONGMIN CHOI 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.4

Heat pumps cover a wide range of heating and cooling applications owing to their means of drawing out heat from ground, air and water at low temperature. In order to acquire performance data for heat pump certification and rating, the calorimeter is used in measuring the heat pump. In conventional approach of measuring the heat pump with standard test conditions, a great amount of energy is used in the calorimeter for cooling and heating. Using innovative ways to enhance the calorimeter performance is significant for energy and cost savings. Therefore, a novel calorimeter was developed for heat pump measurement. Two different flow loop configurations, specified as cases (1) and (2) were adopted. In the case (1), secondary fluid flow through the heat recovery unit was directly from heat pump test unit heat exchanger while in case (2), secondary fluid flow through heat recovery unit was from constant temperature water bath directly. The energy usage of the novel calorimeter based on the impact of each configuration was analyzed. Experiments were conducted using a water-to-water heat pump unit in heating and cooling approach with variation in operating conditions. Energy analyses based on test data indicated that energy reduction of the novel calorimeter was at least 72 % for heating and 69 % for cooling in relation to energy used in conventional calorimeter. Moreover, for novel calorimeter, case (1) resulted in energy savings of at least 9.1 % for cooling and 13 % for heating in relation to case (2). However, for heat pump units with very low capacities, tests measurements were executed using case (2) configuration because the tests in case (1) resulted in large thermal fluctuations such that the steady operating conditions of the water setpoint temperatures at inlet to the indoor and outdoor heat exchangers of the test unit were unattainable.

급속가열환경에서 A12024-T3의 인장특성

김종환(Jong-Hwan Kim),김재훈(Jae-Hoon Kim) 한국항공우주학회 2004 韓國航空宇宙學會誌 Vol.32 No.8

본 연구에서는 비행체 구조재료인 A12024-T3에 대하여 공력가열환경을 모사할 수 있는 복사가열기를 제작하였으며, 1℃/sec~30℃/sec 가열률 범위에서 열기계적 인장특성을 평가 하였다. 가열환경에 따른 재료강도 평가를 위하여 급속가열 인장시험 결과와 일정 온도로 30분 노출후의 인장시험결과를 항복응력 측면에서 비교 고찰하였다. 급속가열 인장시험 결과로부터 시간-온도계수를 응용한 가열률-항복온도 계수를 도출하였으며, 항복응력을 가열률과 항복온도로 표현되는 실험적 master 수식을 제안하였다. 본 연구 결과를 통하여 획득 된 급속가열 인장시험결과들은 초음속 비행체 설계시 선정재료의 안전여유를 판단하는 기 초자료로 활용될 수 있다. The thermomechanical tensile characteristics were evaluated for A12024-T3 under heating rates from 1 ℃/sec to 30℃/sec by using an infrared heating equipment to simulate aerodynamic heating. The rapid heating test results were compared with tensile test results after 1/2 hour exposure in terms of yield stress to investigate the influence of heating condition. A heating rate-yield temperature parameter was suggested for rapid heating based on time-temperature parameters, and master yield stress curve was obtained by using these parameter. These test results can be used for margin of safety of supersonic vehicle structures subjected to aerodynamic heating.

High heat flux test and cooling effect of tungsten brazed mockups with swirl tube

Kim, K.M.,Kim, H.T.,Kim, H.C.,Park, S.H.,Hong, S.H.,Park, H.K.,Ahn, H.J.,Kim, Y.S.,Kim, S.K.,Lee, D.W. Elsevier 2018 Fusion engineering and design Vol.134 No.-

<P><B>Abstract</B></P> <P>It is so important that the bonding technology between tungsten and dissimilar metals for the PFC of ITER and DEMO, KSTAR. The development of tungsten brazing technology was first launched for the KSTAR PFC.</P> <P>Flat type tungsten block was brazed on CuCrZr in vacuum at a temperature of 980 °C for 30 min using silver free brazing alloy. The brazing filler is a 0.05 mm thick-plate made of a Ni-Cu-Mn alloy.</P> <P>Tungsten brazed mock-ups with a swirl and smooth tube were tested at an electron beam facility, KoHLT-EB(Korea heat load test facility-Electron Beam) in KAERI. The high heat flux test was performed for tungsten brazed mock-ups with a swirl and smooth tube under the heat flux of about 5.4–8 MW/m<SUP>2</SUP>. The test results show there are no delamination or failures at the bonding joints during and after all the heat flux test.</P> <P>According to the thermal hydraulic analysis and results of heat flux test, the cooling effect of the smooth tube was better than one of the swirl tube at the conditions of the coolant of about 0.35 MPa and the heat flux of over about 5 MW/m<SUP>2</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The flat type tungsten brazed mockups with a smooth and swirl tube were tested under a heat flux of 5.4–8 MW/m<SUP>2</SUP> up to 220 cycles. </LI> <LI> It was analyzed by ANSYS CFX at a single phase flow and a sub-cooled boiling condition. </LI> <LI> There were no any cracks and delamination in the joints of the two mockups. </LI> <LI> The cooling effect of the sub-cooled boil condition was better than the one of the single phase flow in the smooth tube. </LI> </UL> </P>

Evaluation of Deterioration of Larix kaempferi Wood Heat-treated by Superheated Steam through Field Decay Test for 12 Months(12개월 야외 내후성 시험에 의한 과열증기 열처리된 낙엽송재의 열화 평가)

( Yonggun Park ),( Yeonjung Han ),( Jun-ho Park ),( Hyunwoo Chung ),( Hyunbin Kim ) 한국목재공학회 2018 목재공학 Vol.46 No.5

본 연구에서는 과열증기를 이용하여 열처리한 낙엽송재의 야외 내후성 시험을 통해 부후균과 해충에 대한 저항성을 평가하였다. 12개월간 진행된 야외 내후성 시험 결과, 무처리재는 흰개미에 의한 피해가 두드러지게 나타났지만 방부목재와 과열증기 열처리재에서는 육안으로 관찰되는 피해는 발견되지 않았다. 무처리재와 방부목재는 약 5%의 질량 감소를 보였으며, 과열증기 열처리재는 약 1%의 질량 감소를 보였다. 야외 내후성 시험이 진행된 후 방부목재에 남아있는 방부약제의 함량이 야외 내후성 시험 전보다 감소한 것으로 보아 야외 내후성 시험이 진행되는 동안 방부약제가 일부 용출된 것으로 보이며, 이에 따라 방부목재의 질량 감소가 무처리재와 유사한 수준으로 나타난 것으로 생각되었다. 과열증기를 이용한 열처리는 방부약제 주입과 같은 화학적인 처리 없이 친환경적으로 목재의 부후균과 해충에 대한 저항성을 개선시킬 수 있는 가능성이 확인되었으며, 이를 위하여 장기적인 관찰이 추가적으로 필요할 것이라 생각된다. In this study, the decay resistance of larch wood, which was heat treated by superheated steam, was evaluated by the field decay test. During the field decay test of 12 months, non-treated wood has been severely damaged by termite, however, no visible damage has occurred in the preservative-treated wood and superheated steam heat-treated wood. Results of field decay test showed approximately 5% mass loss of the non-treated wood and the preservative-treated wood, and approximately 1% mass loss of the superheated steam heat-treated wood. After the field decay test for 12 months, the residual amount of preservatives remaining in the preservative-treated wood was lower than that before the field decay test. It was considered that the preservative was partially eluted during the field decay test, and the mass loss of the preservative-treated wood was thought to be similar to that of the non-treated wood. Through this study and additional long-term monitoring test, superheated steam heat treatment can be considered to be an environmental-friendly method to enhance the decay resistance of wood against rot fungi and/or insect without chemical treatment such as preservative injection.

인공피혁의 세탁에 따른 물리적 특성 및 열ㆍ수분 전달 특성 변화 : 환경온ㆍ습도의 변화를 중심으로

안유미,류덕환 啓明大學校 生活科學硏究所 1999 科學論集 Vol.25 No.-

Ten kinds of polyurethane coated artificial leathers, which are emerging rapidly as new fabrics after development of the waterproof and water vapor permeable technique, were used as specimens at this study. Five kinds of specimens with the waterproof and water vapor permeable function and the other five kinds of specimens with only the waterproof were tested at various conditions(environmental temperature : 12℃, 15℃, 18℃, 21℃, 24℃, relative humidity : 45%, 55%). Through hot plate heat transfer test and skin simulating system test the properties of heat and moisture transfer before and after washing were observed. The results of this study are as followings ; 1. When the ground structure was knit rather than fabric, the weight increased with increasing thickness because the degree of yarn freedom was high and the shrinkage was large. 2. In hot plate heat transfer test the change of heat transfer properties by the change of environmental temperatures before and after washing did not have a special tendency at both 45% R.H. and 55% R.H. but the heat transfer decreased as the environmental temperature was high. This trend was more apparent after washing than before washing. The reason is that the convection becomes more active due to the remarkable difference of temperature between hot plate and environmental air. 3. CLO values of specimens of B group with only the waterproof function showed wider fluctuations, comparing to those of A group with the water vapor permeable function had stable CLO values. When the significant difference of CLO values among all of the specimens, A group and B group at each environmental temperature was examined before and after washing in hot plate heat transfer test and skin simulating test for moisture transfer, the significant difference was found out at P<0.05. 4. Through hot plate heat transfer test and skin simulating system test the moisture transfer at 55% R.H. before and after washing was superior to that at 45% RH. And the moisture transfer was active as the environmental temperature was high. Besides, the moisture transfer at A group was easier than that at B group because A group had enough water vapor permeable voids. 5. The change of contact angle as a parameter determining the waterproof and water vapor permeable function decreased considerably after washing. Especially, the decreasing rate of A group with the water vapor permeable function was larger than that of B group.

SEPARATE AND INTEGRAL EFFECT TESTS FOR VALIDATION OF COOLING AND OPERATIONAL PERFORMANCE OF THE APR+ PASSIVE AUXILIARY FEEDWATER SYSTEM

강경호,김석훈,조윤재,박유선,윤병조,배병언 한국원자력학회 2012 Nuclear Engineering and Technology Vol.44 No.6

The passive auxiliary feedwater system (PAFS) is one of the advanced safety features adopted in the APR+, which is intended to completely replace the conventional active auxiliary feedwater system. With an aim of validating the cooling and operational performance of PAFS, an experimental program is in progress at KAERI, which is composed of two kinds of tests; the separate effect test and the integral effect test. The separate effect test, PASCAL (PAFS Condensing Heat Removal Assessment Loop), is being performed to experimentally investigate the condensation heat transfer and natural convection phenomena in PAFS. A single, nearly-horizontal U-tube, whose dimensions are the same as the prototypic U-tube of the APR+ PAFS, is simulated in the PASCAL test. The PASCAL experimental result showed that the present design of PAFS satisfied the heat removal requirement for cooling down the reactor core during the anticipated accident transients. The integral effect test is in progress to confirm the operational performance of PAFS, coupled with the reactor coolant systems using the ATLAS facility. As the first integral effect test, an FLB (feedwater line break) accident was simulated for the APR+. From the integral effect test result, it could be concluded that the APR+ has the capability of coping with the hypothetical FLB accident by adopting PAFS and proper set-points of its operation.

Evaluation of Fracture Strength and Material Degradation for Weldment of High Temperature Service Steel Using Advanced Small Punch Test

Lee, Dong-Hwan The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.9

This paper presents an effective and reliable evaluation method for fracture strength and material degradation of the micro-structure of high temperature service steel weldment using advanced small punch (ASP) test developed from conventional small punch (CSP) test. For the purpose of the ASP test, a lower die with a minimized ${\Phi}$1.5 mm diameter loading ball and an optimized deformation guide hole of ${\Phi}$3 mm diameter were designed. The behaviors of fracture energy (E$\_$sp/), ductile-brittle transition temperature (DBTT) and material degradation from the ASP test showed a definite dependency on the micro-structure of weldment. Results obtained from ASP test were compared and reviewed with results from CSP test, Charpy impact test, and hardness test. The utility and reliability of the proposed ASP test were verified by investigating fracture strength, behavior of DBTT, and fracture location of each micro-structure of steel weldment for test specimen in ASP test. It was observed that the fracture toughness in the micro-structure of FL+CGHAZ and ICHAZ decreased remarkably with increasing aging time. From studies of all micro-structures, it was observed that FGHAZ microstructure has the most excellent fracture toughness, and it showed absence of material degradation.

SEPARATE AND INTEGRAL EFFECT TESTS FOR VALIDATION OF COOLING AND OPERATIONAL PERFORMANCE OF THE APR+ PASSIVE AUXILIARY FEEDWATER SYSTEM

Kang, Kyoung-Ho,Kim, Seok,Bae, Byoung-Uhn,Cho, Yun-Je,Park, Yu-Sun,Yun, Byoung-Jo Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.6

The passive auxiliary feedwater system (PAFS) is one of the advanced safety features adopted in the APR+, which is intended to completely replace the conventional active auxiliary feedwater system. With an aim of validating the cooling and operational performance of PAFS, an experimental program is in progress at KAERI, which is composed of two kinds of tests; the separate effect test and the integral effect test. The separate effect test, PASCAL ($\underline{P}$AF$\underline{S}$ $\underline{C}$ondensing Heat Removal $\underline{A}$ssessment $\underline{L}$oop), is being performed to experimentally investigate the condensation heat transfer and natural convection phenomena in PAFS. A single, nearly-horizontal U-tube, whose dimensions are the same as the prototypic U-tube of the APR+ PAFS, is simulated in the PASCAL test. The PASCAL experimental result showed that the present design of PAFS satisfied the heat removal requirement for cooling down the reactor core during the anticipated accident transients. The integral effect test is in progress to confirm the operational performance of PAFS, coupled with the reactor coolant systems using the ATLAS facility. As the first integral effect test, an FLB (feedwater line break) accident was simulated for the APR+. From the integral effect test result, it could be concluded that the APR+ has the capability of coping with the hypothetical FLB accident by adopting PAFS and proper set-points of its operation.