Heat Transfer and Pressure Loss Characterization in a Channel with Discrete Flush-mounted and Protruding Heat Sources

This work deals with an experimental inv estigation of the conv ectiv e heat transfer and pressu re loss in a rectangular channel with discrete flush-mounted and protruding heat sources. Six protruding obstacle heights, which represen t the range of the dimensionless protrusion of 0 F h r H F 0.805, are studied in this work. The temperatures on the heater surfaces and that of the fluid are collected, and data obtained at steady state are used to calculate the heat transfer coefficients, the Nusselt number, and the pressu re loss coefficient. The resu lts show that at lower Reynolds number, free conv ection cannot be neglected for cases where the discrete heat sources are flush-mounted on the channel floor. For cases of discrete protruding heat sources, heat transfer is dominated by forced conv ection and free conv ection can be ignored. The presence of the protruding heat sources distorts the flow in the channel, causing a substantial increase in heat transfer. Based on the experimental data, empirical correlations for the Nusselt number in terms of Reynolds number, and the dimensionless protruding height, are obtained for each heater by means of multiregression in the range Re s 1,500±6,300 and h r H s 0.151±0.805. The presence of the protruding heat sources increases the pressu re loss dramatically. The resu lts show that the pressu re loss is dominated by the inertial effect. The results also quantify that the pressu re loss coefficient, f, increases as the Reynolds number is decreased and r or h r H is increased. Based on the experimental data, an empirical relationsh ip for the pressu re loss coefficient in terms of Reynolds number and the dimensionless protruding height is obtained.