Effects of structure parameters on heat transfer in round to rectangular nozzles

To understand influence of structure parameters on heat transfer in round to rectangular nozzle (RR nozzle), several RR nozzles were designed. Three parameters were taken into consideration: round to rectangular transforming position, ratio of height to width and arc radius at exit. Three dimensional Navier-Stokes equations were solved with finite volume method. Standard k-ε turbulent model and wall function were used for near wall treatment. The coupling of pressure and velocity were realized with SIMPLE algorithm. Results indicate: under conditions that contour derivative is consecutive, transforming position does not significantly affect heat transfer in RR nozzles; height to width ratio at exit greatly influences heat transfer in RR nozzles and too small ratio would lead to high temperature points on gas side wall; arc radius has an effect on surface temperature of perimeter of gas side wall and too small radius makes circumferential temperature non-uniform.