Experimental study on heat transfer enhancement of gas tube partially filled with metal foam

This paper proposes partially filling a gas tube with metal foam to further enhance the gas heat transfer capability with smaller pressure loss. A wind-tunnel-type gas heat transfer test system was built to investigate the features and effects of this heat transfer enhancement method. The effects of pore density and filling thickness of the metal foam on the gas heat transfer in the tube were studied experimentally and analyzed by determining the performance evaluation criteria (PEC), a comprehensive evaluation index. The results show that for the same porosity and filling rate, a high heat transfer coefficient can be obtained at high pore density; however, the comprehensive evaluation index of metal foam with a lower porosity is higher. Thus, lower porosity metal foam inserted at a higher filling rate, together with a low Reynolds number, leads to more efficient heat transfer.