Experimental verification for the phases separation technique to improve the thermal performance of vertical and inclined wickless heat pipe

Abstract

A flow separation technique is tested experimentally for the thermal performance enhancement of the Thermosyphon Heat Pipe (THP). Flow separation for the vapor rising upward and the condensate flowing downward is used to eliminate the complex interactions between the two phases. Such interactions are found and discussed by previous numerical work published by the authors. Tubes Packing (TP) made of two parallel copper tubes welded contrary to each other with a neighboring openings at central disk are used to grantee the smooth flow through the THP. The THP is made with a suitable dimension for the evaporator, adiabatic and condensation sections. Different operating conditions of filling ratios, supplied heat and inclination angles are tested to monitor the THP thermal performance during transient and steady state operation. The experimental tests results showed that the insertion of TP into the THP enhanced the thermal performance of THP by reducing the transient operation time about 37% and the maximum averaged temperature in the evaporator section about 50%. Also, reduces the variation effects of the filling ratio and the inclination angle on the thermal performance. In general, the results showed that the insertion of the TP reduces the THP thermal resistance about 17% to 62% based on the operating conditions.