Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a slot air jet

Abstract

Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a normal slot air jet is experimental investigated. Present study focuses on the influence of jet-to-plate spacing (Z/Dh) (0.5–10) and Reynolds number (2500–20,000) on the fluid flow and heat transfer distribution. A single slot jet with an aspect ratio (l/b) of about 22 is chosen for the current study. Infrared Thermal Imaging technique is used to capture the temperature data on the target surface. Local heat transfer coefficients are estimated from the thermal images using ‘SMART VIEW’ software. Wall static pressure measurement is carried out for the specified range of Re and Z/Dh. Wall static pressure coefficients are seen to be independent of Re in the range between 5000 and 15,000 for a given Z/ Dh. Nu values are higher at the stagnation point for all Z/ Dh and Re investigated. For lower Z/Dh and higher Re, secondary peaks are observed in the heat transfer distributions. This may be attributed to fluid translating from laminar to turbulent flow on the target plate. Heat transfer characteristics are explained based on the simplified flow assumptions and the pressure data obtained using Differential pressure transducer and static pressure probe. Semi-empirical correlation for the Nusselt number in the stagnation region is proposed.