기존 트랙터 로터리날의 운동분석

이현동,김기대,김찬수,김성환 충남대학교 농업과학연구소 2004 농업과학연구 Vol.31 No.1

In this study, motion characteristics and power requirement of rotary tilling according to shape of conventional rotary blade were measured This study was performed to establish factors which needed to develop energy saving rotary blade. Starting point of edged curve of imported rotary blade was faster than that of domestic rotary blade after measuring and analyzing edged curve of rotary blade. So domestic rotary blade tills much soil than imported rotary blade. In analyzing motion of rotary blade, Rotary blade of A, D type was begun to contact at part 3. Analyzing back surface of rotary blade which contact to soil at critical λ results in contacting at e-f part. In measuring power requirement of rotary blade, specific torque and specific work of rotary blade are 160~170 kgf·m/m², 3,700 kgf·m/m³. It shows power requirement of rotary blade according to shape of rotary blade are very different.

Investigation on the effects of blade thickness for a centrifugal rotary blood pump

Haoyuan Li,Ming-Kui Zhang,Xianwu Luo,Qing-Yu Wu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

A centrifugal rotary blood pump was treated to investigate the effects of blade thickness by numerical simulation, where Reynolds averaged Navier-Stokes method coupling with k-ω SST turbulence model is applied. For comparison, five pumps were designed with different blade thickness distribution from the leading edge to trailing edge. The numerical methods were validated by the comparison of hydraulic performance between the simulation and the experiment for a test pump. Results showed that the thicker blade near leading edge suppresses the separation flow in blade-to-blade passage of pump impeller, and can improve hydraulic efficiency at low flow rate. On the other hand, the blade shape modification by trimming suction side near trailing edge is helpful to reduce the hydraulic loss by suppressing the flow mixing downstream impeller exit. Power loss analysis based on the simulated internal flow indicated that viscous dissipation of mean kinetic energy (VDKE) and turbulence kinetic energy production (TKEP) are main source terms contributing to power loss for the blood pump. The blade thickness near trailing edge changes the interaction between volute tongue and impeller blade, and the trimmed blade is helpful for decreasing the large values of VDKE and TKEP in pump volute compared with the conventional blade. The analysis further indicates that the blade modifications with thickness increment seem to slightly increase the degree of RBCs damage, and the effect of blade thickness on the hemolysis index of the blood pump should be carefully considered. The results are expected to be beneficial to the wide application of centrifugal rotary blood pumps.

A Study on Rotary Weeding Blade Installation Angle for Reduction of Hand Vibration in Working Type Cultivator

Kwon, Tae Hyeong,Kim, Joonyong,Lee, Chungu,Kang, Tae Gyoung,Lee, Byeong-Mo,Rhee, Joong-Yong Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.1

Purpose: Walking type cultivator used for weeding generated excessive handle vibration as well as bouncing motion depending on the weeding speed. This research was conducted to define a design factor of the rotary weeding blades for reducing soil reaction forces as well as hand vibration. Methods: The motion and forces acting on the rotary blades were reviewed to find out the most influencing parameter on hand vibration. The installation angle (IA) of the blade was selected and analyzed to determine the condition of no reaction force less. For removing the unnecessary upward soil reaction, the design factor theory of weeding blade was suggested based on geometrics and dynamics. For evaluation of design factor theory, the experiment in situ was performed base on ISO 5349:1. The vibration $a_{hv}$ and theoretical value $X_{MF}$ were compared with two groups that one was positive group ($X_{MF}$ > 0) and the other was negative group ($X_{MF}$ < 0). Results: $X_{MF}$ was derived from rotational velocity, forward velocity, disk diameter, weeding depth, blade's width and IA of blade. Two groups had significant difference (p < 0.05). In aspect of the group mean total exposure duration, positive group was 17.53% bigger than negative group. When disk radius 100, 150 and 200 mm, minimum IAs were $4{\sim}27^{\circ}$, $3{\sim}15^{\circ}$ and $2{\sim}10^{\circ}$, respectively. A spread sheet program which calculated XMF was developed by Excel 2013. Conclusions: According to this result, minimum IA of weeding blade for soil reaction reduction could be obtained. For reduction hand-arm vibration and power consumption, minimum IA is needed.

A Study on Rotary Weeding Blade Installation Angle for Reduction of Hand Vibration in Working Type Cultivator

권태형,김준용,이춘구,강태경,이병모,이중용 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.1

Purpose: Walking type cultivator used for weeding generated excessive handle vibration as well as bouncing motiondepending on the weeding speed. This research was conducted to define a design factor of the rotary weeding blades forreducing soil reaction forces as well as hand vibration. Methods: The motion and forces acting on the rotary blades werereviewed to find out the most influencing parameter on hand vibration. The installation angle (IA) of the blade was selectedand analyzed to determine the condition of no reaction force less. For removing the unnecessary upward soil reaction, thedesign factor theory of weeding blade was suggested based on geometrics and dynamics. For evaluation of design factortheory, the experiment in situ was performed base on ISO 5349:1. The vibration ahv and theoretical value XMF werecompared with two groups that one was positive group (XMF > 0) and the other was negative group (XMF < 0). Results: XMFwas derived from rotational velocity, forward velocity, disk diameter, weeding depth, blade’s width and IA of blade. Twogroups had significant difference (p < 0.05). In aspect of the group mean total exposure duration, positive group was 17.53%bigger than negative group. When disk radius 100, 150 and 200 mm, minimum IAs were 4 ~ 27°, 3 ~ 15° and 2 ~ 10°,respectively. A spread sheet program which calculated XMF was developed by Excel 2013. Conclusions: According to thisresult, minimum IA of weeding blade for soil reaction reduction could be obtained. For reduction hand-arm vibration andpower consumption, minimum IA is needed.

Tillage Characteristics Estimation of Crank-type and Rotary-type Rotavators by Motion Analysis of Tillage Blades

( Ju Seok Nam ),( Dae Chun Kim ),( Myoung Ho Kim ),( Dae Cheol Kim ) 한국농업기계학회 2012 바이오시스템공학 Vol.37 No.5

This study has been conducted to investigate the applicability of motion analysis of tillage blade for estimation of tillage characteristics of crank-type and rotary-type rotavators. Methods: The interrelation between tillage traces from motion analysis and field test results including rotavating depth, pulverizing ratio and inversion ratio at the same work conditions were analyzed for both crank-type and rotary-type rotavators. The work conditions include working speed of prime mover tractor and PTO speed of rotavators. For the motion analysis, joint conditions of main connecting component were specified considering the actual working mechanism of rotavator. Results: There were important correlations for the trend between motion analysis and field test results. Conclusions: Although further study is needed for applying motion analysis to estimate the accurate tillage related parameters such as rotavating depth, the soil pulverizing ratio and inversion ratio, it could be used to compare the tillage characteristics of various rotavators quickly and simply.

3차원 회전 블레이드에 대한 정적/동적 유체-구조 연계해석

김동현(Dong-Hyun Kim),김유성(Yu-Sung Kim),김동만(Dong-Man Kim),박강균(Kang-Kyun Park) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

In this study, static/dynamic fluid-structure interaction analyses have been conducted for a 3D rotary blade model like a turbo-machinery or wind turbine blade. Advanced computational analysis system based on computational fluid dynamics (CFD) and computational structural dynamics (CSD) has been developed in order to investigate detailed dynamic responses of rotary type models. Fluid domains are modeled using the computational grid system with local grid deforming techniques. Reynolds-averaged Navier-Stokes equations with various turbulence model are solved for unsteady flow problems of the rotating blade model. Detailed static/dynamic responses and instantaneous pressure contours on the blade surfaces considering flow-separation effects are presented to show the multi-physical phenomenon of the rotating blades.

Rotary discharge machine을 이용한 저장매체 제거 시 Blade의 응력분포 해석

정연호(Y. H. Jeong),김찬규(C. G. Kim),조영태(Y. T. Cho),정윤교(Y. G. Jung) 한국기계가공학회 2016 한국기계가공학회 춘추계학술대회 논문집 Vol.2016 No.10

Tillage Characteristics Estimation of Crank-type and Rotary-type Rotavators by Motion Analysis of Tillage Blades

Nam, Ju-Seok,Kim, Dae-Chun,Kim, Myoung-Ho,Kim, Dae-Cheol Korean Society for Agricultural Machinery 2012 바이오시스템공학 Vol.37 No.5

Purpose: This study has been conducted to investigate the applicability of motion analysis of tillage blade for estimation of tillage characteristics of crank-type and rotary-type rotavators. Methods: The interrelation between tillage traces from motion analysis and field test results including rotavating depth, pulverizing ratio and inversion ratio at the same work conditions were analyzed for both crank-type and rotary-type rotavators. The work conditions include working speed of prime mover tractor and PTO speed of rotavators. For the motion analysis, joint conditions of main connecting component were specified considering the actual working mechanism of rotavator. Results: There were important correlations for the trend between motion analysis and field test results. Conclusions: Although further study is needed for applying motion analysis to estimate the accurate tillage related parameters such as rotavating depth, the soil pulverizing ratio and inversion ratio, it could be used to compare the tillage characteristics of various rotavators quickly and simply.

Tillage Characteristics Estimation of Crank-type and Rotary-type Rotavators by Motion Analysis of Tillage Blades

남주석,김대천,김명호,김대철 한국농업기계학회 2012 바이오시스템공학 Vol.37 No.5

Purpose: This study has been conducted to investigate the applicability of motion analysis of tillage blade for estimation of tillage characteristics of crank-type and rotary-type rotavators. Methods: The interrelation between tillage traces from motion analysis and field test results including rotavating depth, pulverizing ratio and inversion ratio at the same work conditions were analyzed for both crank-type and rotary-type rotavators. The work conditions include working speed of prime mover tractor and PTO speed of rotavators. For the motion analysis, joint conditions of main connecting component were specified considering the actual working mechanism of rotavator. Results: There were important correlations for the trend between motion analysis and field test results. Conclusions: Although further study is needed for applying motion analysis to estimate the accurate tillage related parameters such as rotavating depth, the soil pulverizing ratio and inversion ratio, it could be used to compare the tillage characteristics of various rotavators quickly and simply.

Effects of Different Blade Numbers on Radial Exciting Force of Lobe Pump Rotor

Yibin Li,Dongsheng Guo,Zhaojing Fan,Jun Du 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2

In order to clarify the relationship between different blade numbers and radial exciting force of the rotary lobe pump rotor, five rotary lobe pumps with different blade numbers were researched based on the dynamic mesh techniques using RNG k-ε turbulence model and PISO algorithm. The internal flow characteristics in the pump are compared and the influence mechanism of the different blade numbers on the transient flow structure and the exciting force inside the rotor cavity are revealed. Meanwhile, through numerical simulation and experimental verification, the comparative analysis of numerical prediction shows that the relative error is less than 5.6%, and the numerical simulation has higher accuracy. The results show that the number of blade has a significant effect on the flow characteristics and radial exciting force distribution of rotor cavity of the rotary lobe pump. With the increase of the number of blades, the average flow rate and the flow pulsation amplitude of the flow rate at the outlet of the pump are obviously decreased, which effectively inhibits the secondary flow, vortex and the velocity abrupt change between the rotor gaps region of the rotor cavity. The maximum radial exciting force at 6 blade numbers is less 36% than that at 4 blade numbers. A multistage series transition cavity is formed between the high-pressure cavity and the low-pressure cavity when the blades number of 5 and 6 which can effectively reduce the pressure difference between the two sides of the radial gaps. It can reduce the radial leakage, and effectively suppress the instantaneous pressure relief effect caused by the instantaneous opening of the gaps.