Optimal Design for Cooling System of Batteries Using DOE and RSM

Zhen-Zhe Li,Yun-De Shen,Tai-Hong Cheng,Dong-Ji Xuan,Ming Ren,Gui-Ying Shen 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

A hybrid power composed of fuel cell and batteries has become the good strategy for HEV. On the contrary, the produced heat of batteries can affect to the total performance of HEV significantly. In this study, simulation methods with optimization were developed for obtaining the high performance cooling system of batteries. At first, a numerical method for obtaining the temperature distribution of batteries was developed by using CFD. In the following step, several parameters were investigated for selecting design variables with the important effect on the performance of the cooling system of batteries. Finally, an optimization method based on DOE and RSM was obtained through a real optimal design. There was 21.1% reduction on the view of the root mean square temperature between batteries as shown in the optimization result. The developed analysis with optimization can be used to improve the performance of the cooling system of batteries, and these works have made the theoretical basis for simulation and optimization of the cooling system of batteries.

Time-dependent Optimal Heater Control in Thermoforming Preheating Using Dual Optimization Steps

Li, Zhen-Zhe,Heo, Kwang-Su,Seol, Seoung-Yun Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.4

Thermoforming is one of the most versatile and economical processes available for shaping polymer products, but obtaining a uniform thickness of the final product using this method is difficult. Heater power adjustment is very important because the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the steady-state optimum distribution of heater power is first ascertained by a numerical optimization to obtain a uniform sheet temperature. The time-dependent optimal heater input is then determined to decrease the temperature difference through the direction of the thickness using the response surface method and the D-optimal method. The optimal results show that the time-dependent optimum heater power distribution gives an acceptable uniform sheet temperature in the forming temperature range by the end of the heating process.

Time-dependent Optimal Heater Control in Thermoforming Preheating Using Dual Optimization Steps

Zhen-Zhe Li,Kwang-Su Heo,Seoug-Yun Seol 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.4

Thermoforming is one of the most versatile and economical processes available for shaping polymer products, but obtaining a uniform thickness of the final product using this method is difficult. Heater power adjustment is very important because the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper; the steady-state optimum distribution of heater power is first ascertained by a numerical optimization to obtain a uniform sheet temperature. The time-dependent optimal heater input is then determined to decrease the temperature difference through the direction of the thickness using the response surface method and the D-optimal method. The optimal results show that the time-dependent optimum heater power distribution gives an acceptable uniform sheet temperature in the forming temperature range by the end of the heating process.

A study on cooling efficiency using 1-d analysis code suitable for cooling system of thermoforming

Zhen-Zhe Li,호광수,Dong-Ji Xuan,설승윤 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.3

Thermoforming is one of the most versatile and economical processes available for polymer products, but cycle time and production cost must be continuously reduced in order to improve the competitive power of products. In this study, water spray cooling was simulated to apply to a cooling system instead of compressed air cooling in order to shorten the cycle time and reduce the cost of compressed air used in the cooling process. At first, cooling time using compressed air was predicted in order to check the state of mass production. In the following step, the ratio of removed energy by air cooling or water spray cooling among the total removed energy was found by using 1-D analysis code of the cooling system under the condition of checking the possibility of conversion from 2-D to 1-D problem. The analysis results using water spray cooling show that cycle time can be reduced because of high cooling efficiency of water spray, and cost of production caused by using compressed air can be reduced by decreasing the amount of the used compressed air. The 1-D analysis code can be widely used in the design of a thermoforming cooling system, and parameters of the thermoforming process can be modified based on the recommended data suitable for a cooling system of thermoforming.

A Study on Control of Heater Power and Heating Time for Thermoforming

Zhen-Zhe Li,Guang Ma,Dong-Ji Xuan,Seoung-Yun Seol,Yun-De Shen 한국정밀공학회 2010 International Journal of Precision Engineering and Vol. No.

Obtaining a uniform thickness of the final product using thermoforming is difficult, and the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the time-dependent temperature distribution of the total sheets in the storing stage was studied because the temperature after the storing stage is the initial temperature of the heating process. An analytic solution for simulating the storing stage was derived. Using the solved analytic solution, the time-dependent temperature distribution of the total sheets was found out under the condition of assuming that the temperature-dependent specific heat of the ABS sheets was a certain constant value. Finally, the control method for a successful thermoforming using the heater power or heating time was researched in order to improve the quality of the final products. The results show that the satisfied temperature distribution can be obtained by adjusting the heater power or heating time. The method for analysis in this study will be used to improve the quality of the final products.

Optimization for Cooling System of Batteries Having Porous Material Using Design of Experiments

Zhen-Zhe Li,Dong-Ji Xuan,Yong Li,Yun-De Shen 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

A hybrid power composed of fuel cell and batteries has become the reasonable strategy for hybrid electric vehicles. On the contrary,the produced heat by batteries can affect the total performance of hybrid electric vehicles significantly. In this paper, analysis methodsand optimization strategy were constructed for obtaining the high performance cooling system for batteries having porous material. At first, a numerical method for obtaining the temperature distribution of battery pack including porous material was developed byusing CFD technique. In the following step, the cooling systems for batteries with porous material or not were compared for showingthe merit of the cooling system for batteries having porous material. Ultimately, an optimization strategy based on D-optimal DOEmethod was obtained through a real optimal design process. There was 13.3% reduction on the view of the root mean squaretemperature between batteries compared with the original cooling system for batteries as shown in the optimization result. Theconstructed analysis method and optimization strategy can be used to improve the performance of the cooling system for batteries,and these works have made the theoretical basis for simulation and optimization of the cooling system for batteries.

Time-Dependent Optimal Heater Control Using Finite Difference Method

Li Zhen-Zhe,Heo Kwang-Su,Choi Jun-Hoo,Seol Seoung-Yun 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

Thermoforming is one of the most versatile and economical process to produce polymer products. The drawback of thermoforming is difficult to control thickness of final products. Temperature distribution affects the thickness distribution of final products, but temperature difference between surface and center of sheet is difficult to decrease because of low thermal conductivity of ABS material. In order to decrease temperature difference between surface and center, heating profile must be expressed as exponential function form. In this study, Finite Difference Method was used to find out the coefficients of optimal heating profiles. Through investigation, the optimal results using Finite Difference Method show that temperature difference between surface and center of sheet can be remarkably minimized with satisfying Temperature of Forming Window.

열성형에 이용된 수분사 냉각의 특성 예측

리진철(Li Zhen-Zhe),허광수(Heo Kwang-Su),설승윤(Seol Seoung-Yun) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

Thermoforming is one of the most versatile and economical processes available for polymer products. In this study, water spray cooling was used instead of compressed air cooling in order to shorten the cycle time and reduce the cost of compressed air used in cooling process. At first, cooling time using compressed air cooling was predicted in order to check the state of mass production. The ratio of removed energy by compressed air cooling or water spray cooling among the total removed energy was found out in the following step. Finally, the analysis conditions suitable for cooling systems of thermoforming was found out by developed 1-D simulation code. The results using water spray cooling show that cycle time can be reduced because of high cooling efficiency of water spray, and cost of production and noise caused by using compressed air can be reduced by decreasing the amount of the used compressed air.

온도 균일화를 위한 근사 해석기법 개발

리진철(Li Zhen-Zhe),허광수(Heo Kwang-Su),최준호(Choi Jun-Hoo),설승윤(Seol Seoung-Yun) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Thermoforming is one of the most versatile and economical process to produce polymer products. The drawback of thermoforming is difficult to control thickness of final products. Temperature distribution affects the thickness distribution of final products. At first, Duhamel's theorem was used in order to get analytic solution, but the analytic solution was difficult to be applied when the boundary condition is complicate or noncontinuous. In order to compensate the drawback of analytic solution, the solution was found out using integral method. With checking the accuracy, it was found out that 4<SUP>th</SUP> order polynomial was fit to present time-dependent temperature profile in the direction of sheet thickness. Finally, case study was carried out using developed approximate analytic solution under the condition of satisfying requirements of thermoforming.

열성형 과정에서 반응면 기법을 이용한 히터의 비정상 최적제어에 관한 연구

리진철(Li Zhen-Zhe),허광수(Heo Kwang-Su),설승윤(Seol Seoung-Yun) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

Thermoforming is one of the most versatile and economical processes available for the manufacturing polymer products. The drawback of thermoforming is difficult to get uniform thickness of final products. For the distribution of thickness strongly depends on the temperature distribution of sheet, the adjustment of heater power is very important In this paper, an optimization study for getting uniform temperature distribution was carried out using dual optimization steps. At first, the steady state optimal distribution of heater power is searched by numerical optimization to get uniform temperature of sheet surface. In the second step, time-dependent optimal heater inputs have been found out to decrease the temperature difference through the direction of thickness using Rseponse Surface Method and D-optimal method. The optimization results show that the time-dependent optimal heater power distribution gives acceptable uniform sheet temperature in the field of forming temperature.