Zhang, Xiaobing. Simulation and optimization of thermo-fluid systems: microchannel cooling and other applications. Retrieved from https://doi.org/doi:10.7282/t3-38zc-zs46
DescriptionMicrochannel systems for cooling applications such as in thermal management of electronic equipment are investigated and optimized under deterministic and reliability conditions. Numerical simulations are carried out to study the conjugate heat transfer and flow behavior. The numerical model has been validated by comparing with analytical and experimental results. Uncertainties are often significant in the operating and design of thermal systems. Any minor variations in the design variables or operating conditions may lead to system failure. In this study, a microchannel cooling system for a 1 cm x 1 cm electronic chip is studied and optimized under design uncertainties. Three significant design variables or operating conditions are considered: (1) flow rate, (2) channel width or the number of channels, (3) heat flux. The standard deviations for the design variables, which are assumed to be normal distributions, are taken as 5% of the mean values. The acceptable probability of failure is chosen as 0.13%, which is the usually accepted level in reliability studies. Response surfaces are used to represent the thermal and fluid behavior in the microchannel systems. Based on the Polynomial Response Surface (PRS) modeling results, a multi-objective optimization problem is formulated to reduce both pumping power and thermal resistance. Two major practical concerns, hot-spot temperature and pressure difference serve as constraints. With varying weights on the two conflicting objectives, Pareto frontiers for deterministic and reliability cases are determined and compared. The differences demonstrate the importance of uncertainty in the microchannel cooling applications. This study provides more reliable and realistic design solutions for microchannel cooling systems.
This approach may be extended to the simulation, design and optimization of other thermal problems and processes. In this study, the selective laser melting (SLM) gas chamber and chemical vapor deposition (CVD) systems are simulated and optimized as well. It is proven that this basic approach presented here is applicable to a wide variety of thermal fluid systems. Similar concerns and trends arise in the modelling and design of these systems.