Experimental research of fluid flow and convection heat transfer in plate channels filled with glass or metallic particles

Fluid flow and forced convection heat transfer was investigated experimenta lly in a plate channel filled with glass, stainless steel or bronze spheric al particles. The test section was 58 mm x 80 mm x 5 mm with water as the w orking fluid. The local wall temperature distribution was measured along wi th the inlet and outlet fluid temperature and pressures. The porous media g reatly increased the heat transfer coefficient although the hydraulic resis tance was increased even more. The effects of particle diameter, particle t hermal conductivity and fluid velocity were examined for a wide range of th ermal conductivities (from 75.3 W/(mK) for bronze to 0.744 W/(mK) for glass ) and for three nominal particle sizes (0.278, 0.428 and 0.7 mm). The coola nt water flow rate in the porous plate channel ranged from 0.01568 to 0.199 2 kg/s. The Nusselt number and the heat transfer coefficient increased with decreasing bronze particle diameter, but decreased with decreasing glass p article diameter. A modified criterion was developed to judge the effect of d(p) on the heat transfer coefficient. The Nusselt number and the heat tra nsfer coefficient increased with increasing thermal conductivity of the pac king material. (C) 1999 Elsevier Science Inc. All rights reserved.