This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat...This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.展开更多
This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat...This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.展开更多
为优化量热器内铜管的传热,明确高效冷凝的核心影响因素,为第二制冷剂量热器性能提升提供技术支撑,本研究采用VOF(Volume of Fluid)多相流模型,结合量热器实际运行工况,通过数值模拟系统探究量热器内光滑圆管、圆形翅片管及螺纹管外R134...为优化量热器内铜管的传热,明确高效冷凝的核心影响因素,为第二制冷剂量热器性能提升提供技术支撑,本研究采用VOF(Volume of Fluid)多相流模型,结合量热器实际运行工况,通过数值模拟系统探究量热器内光滑圆管、圆形翅片管及螺纹管外R134a的冷凝换热过程。研究表明,圆形翅片管因换热面积较光滑圆管增幅达98%,较光滑圆管换热量提升97%;螺纹管则借助螺旋结构诱导二次流动,在换热面积仅较光滑圆管增加14.5%的情况下,换热量提升26.8%,且展现出更优异的排液性能;相界面动态分析表明,翅片管呈现翅根与翅顶的差异冷凝特性,而螺纹管通过表面张力梯度作用形成均匀小液滴脱落模式。本研究结果为量热器内铜管强化传热设计提供了重要理论与数据依据,同时证实表面几何结构与润湿性的协同优化是实现R134a等制冷剂在管外高效冷凝的关键途径。展开更多
文摘This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.
文摘This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.
文摘为优化量热器内铜管的传热,明确高效冷凝的核心影响因素,为第二制冷剂量热器性能提升提供技术支撑,本研究采用VOF(Volume of Fluid)多相流模型,结合量热器实际运行工况,通过数值模拟系统探究量热器内光滑圆管、圆形翅片管及螺纹管外R134a的冷凝换热过程。研究表明,圆形翅片管因换热面积较光滑圆管增幅达98%,较光滑圆管换热量提升97%;螺纹管则借助螺旋结构诱导二次流动,在换热面积仅较光滑圆管增加14.5%的情况下,换热量提升26.8%,且展现出更优异的排液性能;相界面动态分析表明,翅片管呈现翅根与翅顶的差异冷凝特性,而螺纹管通过表面张力梯度作用形成均匀小液滴脱落模式。本研究结果为量热器内铜管强化传热设计提供了重要理论与数据依据,同时证实表面几何结构与润湿性的协同优化是实现R134a等制冷剂在管外高效冷凝的关键途径。
