Assessment of Periodic Flow Assumption for Unsteady Heat Transfer in Grooved Channels

2004 ◽  
Vol 126 (6) ◽  
pp. 1044-1047 ◽  
Author(s):  
Yongmann M. Chung ◽  
Paul G. Tucker

Numerical studies of unsteady heat transfer in grooved channel flows are made. The flows are of special relevance to electronic systems. Predictions suggest a commonly used periodic flow assumption (for modeling rows of similar electronic components) may not be valid over a significant system extent. It is found that the downstream flow development is strongly dependent on geometry.

Volume 4 ◽  
2004 ◽  
Author(s):  
T. Icoz ◽  
N. Verma ◽  
Y. Jaluria

The design of cooling systems for electronic equipment is getting more involved and challenging due to increase in demand for faster and more reliable electronic systems. Therefore, robust and more efficient design and optimization methodologies are required. Conventional approaches are based on sequential use of numerical simulation and experiment. Thus, they fail to use certain advantages of using both tools concurrently. The present study is aimed at combining simulation and experiment in a concurrent manner such that outputs of each approach drives the other to achieve better engineering design in a more efficient way. In this study, a relatively simple problem involving heat transfer from multiple heat sources, simulating electronic components, located in a horizontal channel was investigated experimentally and numerically. Two experimental setups were fabricated for air and liquid cooling experiments to study the effects of different coolants. De-ionized water was used as the liquid coolant in one case and air in the other. The effects of separation distance and flow conditions on the heat transfer and fluid flow characteristics were investigated in details for both coolants. Cooling capabilities of different cooling arrangements were compared and the results from simulations and experiments were combined to provide quantitative inputs for the design. The domains over which experimental or the numerical approach is superior to the other are determined. Simulations are used to guide the experiments and vice versa. It is found that the proposed optimization methodology can be implemented in the design of cooling systems for electronic components for faster and more efficient convergence. This methodology can also be extended to more complex and practical electronic systems.


2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110259
Author(s):  
Xiao Guoquan ◽  
Wang Huaming ◽  
Chen Lin ◽  
Hong Xiaobin

In the process of vehicle development, the unsteady simulation of thermal management system is very important. A 3D-CFD calculation model of vehicle thermal management is established, and simulations were undertaken for uphill with full loads operations condition. The steady results show that the surface heat transfer coefficient increases to the quadratic parabolic relationship. The unsteady results show that the pulsating temperatures of exhaust and external airflow are higher than about 50°C and lower than 10°C, respectively, and the heat dissipating capacities are higher than about 11%. Accordingly, the conversion equivalent exhaust velocity increased by 1.67%, and the temperature distribution trend is basically the same as unsteady results. The comparison results show that the difference in the under-hood should be not noted, and that the predicted exhaust system surface temperatures using steady velocity equivalent method are low less 10°C than the unsteady results. These results show the steady velocity equivalent method can be used to predict the unsteady heat transfer effect of vehicle thermal management system, and the results obtained by this method are basically consistent with the unsteady results. It will greatly save computing resources and shorten the cycle in the early development of the vehicle thermal management system.


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