The Experts below are selected from a list of 17865 Experts worldwide ranked by ideXlab platform

Jiinyuh Jang - One of the best experts on this subject based on the ideXlab platform.

  • 3 d numerical and experimental analysis of a built in motorized high speed spindle with helical water Cooling Channel
    Applied Thermal Engineering, 2008
    Co-Authors: C H Chien, Jiinyuh Jang
    Abstract:

    Abstract The purpose of this paper is to numerically and experimentally analyze the three-dimensional fluid motion and temperature distributions in a built-in motorized high-speed spindle with a helical water Cooling Channel. The effects of different heat sources ( q  = 60 W, 120 W and 240 W, which correspond to heat flux q ″ of 1.43 W/cm 2 , 2.8652 W/cm 2 and 5.7304 W/cm 2 , respectively), Cooling water flow rate (0.4 L/min, 0.8 L/min and 1.2 L/min, which correspond to Cooling water velocity 0.24 m/s, 0.48 m/s and 0.72 m/s, respectively) are examined in detail. The model is based upon a custom-built high performance spindle, which is used in the printed-circuit board (PCB) industry, of 1.5 kW and a maximum speed of 160,000 rpm. The results indicated that almost all the hot spots are concentrated near the center of the spindle axis, and temperature increase can be significantly reduced with helical water-Cooling. The predicted temperature distribution of the spindle housing is in good agreement with the result obtained from experiments. It is also shown that the heat transfer coefficient h varies with V 0.184 . Regression analysis was conducted to obtain Nu  = 4.63 Re 0.184 , which can be applied for 5 × 10 4 Re 5 .

Junho Kwon - One of the best experts on this subject based on the ideXlab platform.

  • performance improvement of hot stamping die for patchwork blank using mixed Cooling Channel designs with straight and conformal Channels
    Applied Thermal Engineering, 2020
    Co-Authors: Junho Kwon
    Abstract:

    Abstract Although the Cooling Channel is a crucial factor for improving the performance of a hot stamping die, only a limited number of studies have been conducted concerning its design technology for patchwork blanks. In this study, a mixed Cooling Channel (MCC) is proposed to improve the Cooling performance of the hot stamping die for patchwork blanks. The MCC is a combination of the straight Cooling Channel (SCC) and conformal Cooling Channel (CCC). The Cooling capacity, average temperature, standard deviation, and figure of merit (FOM) of the SCC, CCC, and MCC are estimated by conducting three-dimensional transient thermo-fluid simulations. The optimum mass flow ratio of the MCC is determined to be 10% considering the Cooling capacity, average temperature, and standard deviation. The MCC exhibits superior Cooling performance to the SCC and CCC for all performance indicators because it effectively cools both the heat accumulated patch and the wide blank. In addition, the daily production of the MCC is 7.6–9.0% greater than that of the SCC, and 5.8–6.8% greater than that of the CCC.

Katsumi Hiraoka - One of the best experts on this subject based on the ideXlab platform.

  • analysis of heat transfer and optimum structural design for Cooling Channel of supersonic nozzle
    한국항공우주학회 학술발표회 논문집, 2008
    Co-Authors: Takeshi Kagawa, Tomohiro Niimura, Katsumi Hiraoka
    Abstract:

    The purpose of this study is optimum structural design for Cooling Channel of supersonic nozzle for rockets. Nowadays. there are two types of structure of Cooling system for supersonic nozzle. One is using Cooling pipe around the supersonic nozzle for Cooling. The other is making Cooling Channel around the supersonic nozzle for Cooling. Later case does not need brazing. And the advantage of later case is using copper of Cooling Channel. Copper has high coefficient of thermal conductivity. Later case is able to be made by cast. So, production run for Cooling system of supersonic nozzle is shorter than that for the former case. Although reliability of the later case is higher than that for the former case, because of no brazing, mass of the later case is heavier than that of the former case. Then, it is needed that mass of the later case will be reduced with optimum structural design. We chose the later case and do optimum structural design by using two softwares, fluid analysis software FLUENT and structure analysis software NASTRAN. The rockets are able to load more payloads by optimum structural design. Thereby we are able to decrease per unit weight cost to lunch rockets.

  • analysis of heat transfer and optimum structural design for Cooling Channel of supersonic nozzle
    한국항공우주학회 학술발표회 논문집, 2008
    Co-Authors: Takeshi Kagawa, Tomohiro Niimura, Katsumi Hiraoka
    Abstract:

    The purpose of this study is optimum structural design for Cooling Channel of supersonic nozzle for rockets. Nowadays. there are two types of structure of Cooling system for supersonic nozzle. One is using Cooling pipe around the supersonic nozzle for Cooling. The other is making Cooling Channel around the supersonic nozzle for Cooling. Later case does not need brazing. And the advantage of later case is using copper of Cooling Channel. Copper has high coefficient of thermal conductivity. Later case is able to be made by cast. So, production run for Cooling system of supersonic nozzle is shorter than that for the former case. Although reliability of the later case is higher than that for the former case, because of no brazing, mass of the later case is heavier than that of the former case. Then, it is needed that mass of the later case will be reduced with optimum structural design. We chose the later case and do optimum structural design by using two softwares, fluid analysis software FLUENT and structure analysis software NASTRAN. The rockets are able to load more payloads by optimum structural design. Thereby we are able to decrease per unit weight cost to lunch rockets.

C H Chien - One of the best experts on this subject based on the ideXlab platform.

  • 3 d numerical and experimental analysis of a built in motorized high speed spindle with helical water Cooling Channel
    Applied Thermal Engineering, 2008
    Co-Authors: C H Chien, Jiinyuh Jang
    Abstract:

    Abstract The purpose of this paper is to numerically and experimentally analyze the three-dimensional fluid motion and temperature distributions in a built-in motorized high-speed spindle with a helical water Cooling Channel. The effects of different heat sources ( q  = 60 W, 120 W and 240 W, which correspond to heat flux q ″ of 1.43 W/cm 2 , 2.8652 W/cm 2 and 5.7304 W/cm 2 , respectively), Cooling water flow rate (0.4 L/min, 0.8 L/min and 1.2 L/min, which correspond to Cooling water velocity 0.24 m/s, 0.48 m/s and 0.72 m/s, respectively) are examined in detail. The model is based upon a custom-built high performance spindle, which is used in the printed-circuit board (PCB) industry, of 1.5 kW and a maximum speed of 160,000 rpm. The results indicated that almost all the hot spots are concentrated near the center of the spindle axis, and temperature increase can be significantly reduced with helical water-Cooling. The predicted temperature distribution of the spindle housing is in good agreement with the result obtained from experiments. It is also shown that the heat transfer coefficient h varies with V 0.184 . Regression analysis was conducted to obtain Nu  = 4.63 Re 0.184 , which can be applied for 5 × 10 4 Re 5 .

Weixing Zhou - One of the best experts on this subject based on the ideXlab platform.

  • effect of Cooling Channel geometry on re cooled cycle performance for hydrogen fueled scramjet
    International Journal of Hydrogen Energy, 2010
    Co-Authors: W Bao, Jiang Qin, Weixing Zhou
    Abstract:

    Developing fuel with higher heat sink is widely carried out to meet the Cooling requirement for an airbreathing hypersonic vehicle. However, a Re-Cooled Cycle has been newly proposed for a regeneratively cooled scramjet to reduce the fuel flow for Cooling. Fuel heat sink (Cooling capacity) is repeatedly used to indirectly increase the fuel heat sink. Parametric sensitivity analysis of Re-Cooled Cycle of a hypersonic aircraft is explored. An analytical fin-type model for incompressible flow in smooth-wall rectangular ducts in terms of hydrodynamic, thermal, power balance and Mach number constraints is proposed. Based on this model, the difference of the Cooling Channel structure design between Re-Cooled Cycle and regenerative Cooling is discussed, and a new optimization index is introduced for Re-Cooled Cycle. The sensitivity of the cycle performance to Cooling Channel geometry is investigated, and the optimal performance of a Re-Cooled Cycle is obtained by satisfying constraints. The differences of the effect of Channel design variables between Re-Cooled Cycle and regenerative Cooling are also discussed.