Heat transfer enhancement on saturated porous samples using electrostatic precipitator process in k-ε turbulent model

Abstract

An influence of the electrostatic precipitator process was numerically investigated for heat transfer enhancement on saturated porous samples in a k-ε turbulent model. The condition of the water entering a test section was the inlet temperature was 30 oC (303 K), and inlet velocity was tested in the range of 1 – 2.5 m/s. The electrical voltage and time varied between 0 – 30 kV and 0 – 1 s, respectively. The initial temperature of saturated porous samples was 10 oC (283 K), and both first and second samples were set in semicircle shapes. The numerical results within the water channel showed that the electric field and electric potential zone appeared and were concentrated when using the electrostatic precipitator process. The high electric voltage could increase disturbance and turbulence within the water channel. The maximum flow field zone appeared above the saturated porous sample area, and the maximum velocity field increased with the inlet velocity and electrical voltage. The maximum pressure was increased to the high voltages, but the pressure was marginally increased with high inlet velocity. The vorticity contour for an electrostatic precipitator process was more concentrated than without the electrostatic precipitator process. Therefore, the temperature contour line in case of high inlet velocity, electrical voltage, and time can be more disturbing than the other cases. In addition, heat from the water was transferred within the sample, so the temperature within the porous sample gradually increased. The fluid velocity within the front porous sample was more within the saturated porous samples than within the porous back sample. Therefore, the flow could move through and within the samples and induce temperature within both saturated porous samples. Finally, the heat transfer within samples was enhanced by fluid flow in the water channel, so the local heat transfer coefficient within samples was induced by the fluid velocity in the water channel.