变流量超临界CO_(2)传热特性实验设计

Experimental design of variable flow supercritical CO_(2)heat transfer characteristics

随着我国“双碳”目标的确立,二氧化碳作为具有较优环保性能的自然工质,是制冷剂替代工作中被广泛关注的研究对象。搭建了变流量超临界二氧化碳(CO_(2))传热特性实验台,对不同入口压力、质量通量、管径下水平微通道管内换热特性进行了探究。结果表明,超临界CO_(2)换热系数随压力的升高而减小,随着质量通量的增大而增大,随着管径的增大而减小。分析可知,影响换热的主要因素是物性的变化,换热系数由于在临界点附近物性的突变存在峰值,实验中获得了不同参数对超临界CO_(2)换热的影响规律。本实验装置和实验内容能够较好地用于相关专业的实验教学,也为超临界CO_(2)换热设备和冷热系统的设计提供指导。

With the establishment of the“double carbon”goal in China,carbon dioxide(CO_(2)),as a natural working medium with better environmental protection performance,has been widely concerned in the research of refrigerant replacement.In this paper,an experimental platform for heat transfer characteristics of supercritical CO_(2) with variable flow rate has been set up to investigate the heat transfer characteristics in horizontal microchannels under different inlet pressures,mass fluxes,and pipe diameters.The results show that the heat transfer coefficient of supercritical CO_(2) decreases with the increase of pressure,increases with the increase of mass flux,and decreases with the increase of pipe diameter.It can be seen from the analysis that the main factor affecting the heat transfer is the change of physical properties.The heat transfer coefficient has a peak value due to the sudden change of physical properties near the critical point.The influence of different parameters on the heat transfer of supercritical CO_(2) was obtained in the experiment,which provides guidance for the design of supercritical CO_(2) heat exchange equipment and cooling and heating systems.