Contents lists available at ScienceDirect International Communications in Heat and Mass Transfer journal homepage: www.elsevier.com/locate/ichmt Study of conjugate heat transfer from the impingement of an inclined free slot jet onto the moving hot surface Shashikant Pawar, Devendra Kumar Patel ⁎ School of Mechanical Engineering, Vellore Institute of Technology, Vellore, India ARTICLE INFO Keywords: Conjugate heat transfer Oblique impinging jet Moving surface Incompressible turbulent flow RANS ABSTRACT A dimensionless numerical investigation of turbulent flow and heat transfer characteristics due to the im- pingement of a free inclined slot jet onto the moving hot surface has been performed using the k - ω turbulence model. The parameters considered for the investigation are: the Reynolds number, impingement angle and plate velocity. The influence of parameters on the properties such as the pressure and velocity profiles, skin-friction coefficients, Nusselt number, interface temperature, and the location of stagnation has been presented. The displacement of stagnation point depends primarily on ϕ, whereas the effect of plate velocity is less significant. These relocations are found in between X = - 2 to 0. The effect of plate velocity on average skin-friction coefficient is continuously decreasing with increase in jet angle. A continuous increase in average Nu has been found with increase in Re for all values of ϕ and U p considered in the present study. It is revealed that the change in plate velocity has more influence on the average Nu for lower angles of impingement. Further reduction in the impingement angle shows an adverse effect on the average Nu. Correlations have been developed for Nusselt number at different zones based on the parameters considered for the study. 1. Introduction Heat transfer with jet impingement technique is broadly used in numerous engineering and industrial applications such as electronic chip cooling [1], turbine blade cooling [2], furnace heating [3], tem- pering of glass and metal sheets [4], fabric drying [5], and due to their distinctive features of heat and mass transfer. The intricate flow over the surface with the variation in flow direction makes it challenging to predict the heat transfer process analytically and experimentally. The numerical simulation appropriates a vital role in this field to predict heat transfer characteristics. The cooling incident of jet flow on the target surface is inevitable in heat transfer literature. Many authors have reported the flow and heat transfer characteristics for the jet im- pingement over the target surface. There are several review papers available in the area of impinging jets [6–9]. It is to be noted that the slot jet impingement provides high heat transfer for the jet spacing about six times the nozzle diameter [10,11]. The inclined impinging jet has numerous applications in the heat transfer process due to its capability to yield high localized and averaged heat transfer coefficients. The demand for non-uniform cooling or heating in industrial applications is fulfilled with the inclined jet im- pingement system. Only a few works have been reported in the im- pingement of inclined jet [10–14]. Goldstein and Franchett [12] measured the isotherms and contours of heat transfer using a tempera- ture sensitive liquid crystal technique. The parameters selected were the Reynolds number (Re), jet-to-plate spacing and jet inclination in the range of 10, 000 - 30, 000, 4 - 10, and 30 ° - 90° respectively. It was noted the displacements of the maximum heat transfer with reference to the origin of the plate. Yan and Saniei [13] determined the local heat transfer coefficients for the impingement of an inclined circular air jet to the flat plate. The parameters investigated were: the Re in a range of 10, 000 - 23, 000, oblique angles varied from 45 ° - 90°, and jet-to-plate spacing in a range of 2 - 10. It was concluded that the shifting of maximum heat transfer is primarily depends on the jet angle. Beitelmal et al. [14] investigated the effect of jet inclination (40 ° - 90°), Re (4000- 12000) and nozzle-to plate spacing (4–12) on the local Nusselt number (Nu) distribution. In the experiment, a two-dimensional turbulent slot jet was impinging onto the uniform heated surface. They have developed a local Nu correlations in different zones dependent on parameters of the jet inclination, impingement distance and Re. Eren and Celik [17] ex- amined the effect of jet parameters that were crucial in the cooling of a hot surface under the inclined impingement of a planar jet. The para- meters investigated were: the Re in a range of 5860 - 11, 606, angle of impingement in a range of 30 ° - 90°, and impingement distance ranging from 4 to 10. It was shown a correlation for the ratio of local tempera- tures to minimum temperature on the impingement surface as a function https://doi.org/10.1016/j.icheatmasstransfer.2019.104429 ⁎ Corresponding author. E-mail address: devendra21082@gmail.com (D.K. Patel). International Communications in Heat and Mass Transfer 111 (2020) 104429 0735-1933/ © 2019 Elsevier Ltd. All rights reserved. T