What are the factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction?
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The factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction include geometrical features, such as diverged cross-sections, intermittent channels, and curved channel profiles, which enhance heat transfer and attenuate flow instability . The height of square micro pin fins also influences the pressure drop and heat transfer behavior, with higher fin configurations providing a more uniform and lower wall temperature distribution . The wedge angle in microchannel designs affects the Nusselt number and thermo-hydraulic performance, with a wedge angle of 15° showing better performance in terms of heat transfer and overall thermal resistance . Additionally, the arrangement of channel widths in mini-channel heat sinks can significantly impact flow uniformity and reduce overall thermal resistance .
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01 Jul 2020 | The provided paper does not discuss the factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction. |
| The provided paper does not discuss the factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction. | |
| The provided paper does not discuss the factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction. | |
28 Sep 2022 | The provided paper does not mention anything about the factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction. |
| The provided paper does not mention anything about the factors affecting the coefficient of performance in two-phase microchannel heat sinks with uniform void fraction. |
Related Questions
What is research gap in optimizing the micro heat sinks?10 answersThe research gap in optimizing micro heat sinks primarily revolves around addressing the challenges of thermal management in miniaturized electronic devices, where the balance between efficient heat removal and system constraints such as pressure drop, uniform temperature distribution, and material optimization remains critical. Despite advancements, several areas require further exploration to enhance the performance of micro heat sinks.
Firstly, the use of novel coolants like ammonia gas has shown potential in reducing thermal resistance significantly compared to traditional air-cooled systems, yet the exploration of alternative gaseous or liquid coolants with superior thermal properties is needed to further improve efficiency. Additionally, the design of microchannel heat sinks faces the challenge of high pressure drop and non-uniform temperature distribution, which necessitates innovative structural designs like the double-layer structured heat sink to enhance heat transfer efficiency and achieve uniform temperature distribution.
The geometric design of pin fins in mini heat sinks also presents an opportunity for optimization, as different shapes (rectangle, cylindrical, spiral) directly impact the heat transfer coefficient and pressure drop, indicating a need for comprehensive studies to identify the most efficient fin geometries. Moreover, the optimization of micro-jet impingement heat sinks through parametric studies and design optimization reveals a trade-off between thermal resistance and pumping power, suggesting that further research is required to optimize these parameters for enhanced cooling performance.
The axial conduction loss in microchannel heat sinks due to small flow rates and short channel lengths is another area where conventional models fall short, highlighting the need for multi-dimensional analytical models to accurately capture the thermal performance and guide design improvements. Furthermore, the application of surrogate analysis and evolutionary algorithms in the optimization process has shown promise in identifying optimal designs by balancing thermal resistance and pumping power, yet the sensitivity of objective functions to design variables along the Pareto optimal front warrants deeper investigation.
The integration of nonlocal thermal-fluid-solid modeling with optimization methods like particle swarm optimization (PSO) and genetic algorithms (GA) for heat sink design has demonstrated the potential for rapid and rigorous solution generation, but the effectiveness and efficiency of these optimization tools in various design scenarios remain to be fully explored. Additionally, the thermal-hydraulic performance of converging-diverging microchannel heat sinks suggests that further research into channel geometry could yield improvements in heat transfer coefficients and pressure drop management.
Lastly, the phenomenon of critical heat flux (CHF) in two-phase transport within microchannels and its dependence on coolant properties, flow rate, and heat sink design underscores the need for a better understanding of CHF to prevent device damage and enhance cooling capacity.
In summary, the research gap in optimizing micro heat sinks encompasses the exploration of novel coolants and materials, innovative design geometries, advanced modeling and optimization techniques, and a deeper understanding of thermal phenomena like CHF to achieve superior thermal management in miniaturized electronic devices.
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Gupta et al. optimized the geometric parameters and coolant inflow states of perforated micro pin-fins (MPFs) heat sinks using NSGA-II, focusing on Nusselt number and friction factor to evaluate hydro-thermal performances. Ge et al. combined evolutionary algorithms with decision-making techniques to optimize the structure of minichannel heat sinks, considering thermal resistance and pumping power as conflicting objectives. Khan et al. employed a genetic algorithm to minimize the entropy generation rate in microchannel heat sinks, indicating an improved overall performance.
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How does the heat transfer coefficient affect the thermal performance ratio?5 answersThe heat transfer coefficient has a significant impact on the thermal performance ratio. Experimental research conducted by Sundar et al.showed that using hybrid nanofluids with higher heat transfer coefficients in a heat pipe resulted in lower wall temperatures at the evaporator and condenser sections, leading to improved thermal performance. Additionally, the study found that the heat transfer coefficients of the evaporator and condenser increased when using hybrid nanoparticles based nanorefrigerants compared to the base fluid. Another study by Houanalyzed the effects of heat transfer on the net work output and indicated thermal efficiency of an air standard Dual cycle. The results showed that higher heat transfer to the combustion chamber walls reduced the peak temperature and pressure, resulting in lower work per cycle and efficiency. Therefore, a higher heat transfer coefficient generally leads to improved thermal performance, while a lower heat transfer coefficient can negatively impact the performance.
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