Hydrothermal performance of a stepped heat pipe

This study elucidates the hydrothermal characteristics of a capillary-driven stepped heat pipe (SHP). An axisymmetric numerical simulation is performed to analyze the effects of step pattern, area ratio (AR), evaporator length (LE), and wick parameters on the system characteristics. The results of the numerical model show good agreement with data from literature. These results suggest that superior performance can be achieved with a two-sided step and a step with sudden contraction with an enlarged evaporator. SHPs with a large area ratio (AR > 1) and a long evaporator yield superior thermal and capillary performances; those with a small condenser diameter (AR < 1) are more likely to experience dryout. Wick parameters, such as porosity (ε) and wick type, play a vital role in the system performance. Numerical results under the studied conditions can provide a clear engineering guide for the design of SHPs used in various engineering applications.