Thermal performance analysis of heat transfer in pipe by using metal foam

Abstract

In this work, turbulent forced convection heat transfer in a circular horizontal pipe with insert of metal foam under the condition of constant heat flux is experimentally investigated. The Nusselt number (Nu) and friction factor (f) were tested under heat flux (31.8 and 42.4 )KW/m2 and water flow rates (3, 6 and 9) lit/min. Circular copper pipe with dimensions of 0.6 m in length, 0.025 m in diameter, and 0.001 m in thickness acts as the test section for the current investigation. It is heated by an electric heater mounted outside the pipe. The foam has pores per inch ranging from (10 to 40) PPI and porosity between ( 0.89 and 0.93).The water flowing through the pipe has a regular input temperature of 32°C.The temperature was measured along the pipe distributed in seven sections of the wall, in addition to measuring the temperature of entering and exiting the water from the pipe. The results show that, with a heat flux of 42.4 KW/m2, the copper metal foam of 40 PPI gives a higher increase in average Nusselt number up to 73% as compared to metal foam of 10 PPI of 63.74%. The difference in pressure drop between pipes with and without metal foam varies just slightly at 10 PPI, but becomes greater at 40 PPI.