Heat transfer characteristics of hot surface using high alcohol surfactant by impinging liquid jet

Abstract

In the present study, an experimental investigation has been carried out to analyze the effect of surfactant on heat transfer characteristics of a circular impinging liquid jet. A rectangular stainless steel foil (AISI-304, 0.15 mm thick), used as the target surface, was electrically heated to obtain the required initial temperature. A single-phase circular water jet of diameter 1.38 mm is allowed to impinge on the hot surface. Thermal images of the target surface during liquid jet impingement were recorded by using an infrared camera (A655sc, FLIR System) positioned on the side of the target surface opposite to the impinging nozzle. The distribution of heat flux on the target surface is evaluated from the recorded thermal images during transient cooling. Tests were performed for an initial surface temperature of 500 °C, Reynolds number (8893 ≤ Re ≤ 12847) and nozzle to plate distance was l/d = 2.5. Experiments have been performed using 2-Ethyl Hexanol added water solution at different concentration (0–400 ppm). Surface heat flux distribution during transient cooling of hot surface is obtained. It was observed that the surface heat flux increases with the rise in the jet Reynolds number and achieves its maximum at surfactant concentration of 200 ppm at stagnation point (6.2 MW/m2 at Re = 8893 to 6.5 MW/m2 at Re = 12847; 200 ppm).