高温太阳能吸热管在非均匀热流下的温度研究及结构优化

对腔式管状集热器在非均匀受热条件下进行温度场和热应力场的模拟。研究发现周向温差的不同造成吸热管的热变形分布不同,且吸热管后半段热变形最大;同时,太阳能辐射量随时间变化导致热流密度和吸热管壁面上的周向温差都在发生变化。鉴于此,分别从腔式集热器吸热管的结构、工作介质物性等方面入手以解决非均匀热流带来的形变问题。通过改变吸热管的结构、选择较薄的壁厚、降低管径、增大进口流速及掺入纳米粒子均能有效减小吸热管的周向温差,从而减少热变形问题。

TEMPERATURE STUDY AND STRUCTURAL OPTIMIZATION OF HIGH TEMPERATURE SOLAR ABSORBING TUBE BY NON-UNIFORM HEAT FLUX

In this paper,the numerical simulation method is used to study the temperature field and thermal stress field of the cavity collector under non-uniform heating conditions,which shows that the difference in circumferential temperature causes different thermal deformation of the absorbing tube,and the deformation on the latter half of the absorbing tube is the largest.Meanwhile,with the change of solar radiation,both the heat flux density and the circumferential temperature difference on the wall of the absorbing tube are varying.Given this,the structure of tube and the physical properties of the working medium are studied to solve the deformation problem caused by the non-uniform heat flux.By changing the structure of the absorbing tube,selecting a thin wall thickness,decreasing the outer diameter,increasing the inlet mass flow rate,and incorporating the nanoparticles,the circumferential temperature difference and thermal deformation of the absorbing tube can be effectively reduced.