Steady State Operation of Cylindrical Loop Heat Pipe Evaporators.

摘要

The loop heat pipe evaporators operating under steady state conditions were numerically investigated to describe evaporator characteristics and evaluate evaporator performance. Numerical solutions were obtained for conjugate flow and heat transfer in primary evaporator components. Two typical geometrical configurations used for the cylindrical LHP evaporator, non-bayonet evaporator and bayonet evaporator, were considered to examine the bayonet effects on evaporator operation. It was found that the presence of a bayonet significantly affects the flow and heat transfer in the liquid core and helps to prevent vapor bubbles from accumulating inside the liquid core. The influences of input heat flux, inlet liquid sub cooling , external loop resistance and effective thermal conductivity of the wick structure on evaporator performance were also studied. It was observed that increasing the applied heat flux and inlet liquid subcooling decreases the maximum temperature in the liquid core and helps to prevent vapor formation in the liquid core, which is favorable for proper evaporator operation. Decreasing the external loop resistance and effective thermal conductivity also decreases the maximum temperature in the liquid core. Additionally increasing the applied heat flux and liquid subcooling significantly enhances the cooling capability of the liquid in the bayonet. This helps to prevent vapor bubbles from accumulating in the liquid core.