Heat Transfer in Turbulent Boundary Layers of Conical and Bell Shaped Rocket Nozzles with Complex Wall Temperature

Abstract

The objective of this article is to perform detailed analysis of heat transfer in accelerated supersonic nozzle flows with cooled walls. Since most of the heat transfer occurs near the nozzle walls, correct prediction of the boundary layer under strong adverse pressure gradient is therefore required to achieve high fidelity numerical prediction. In this study, a two-equation SST-V turbulence model is used in conjunction with a second-order explicit-implicit method to solve axisymmetric compressible Navier-Stokes equations. First, the effect of the inlet pipe diameter and the associated contraction area on the heat transfer is studied in nozzles having 15 and 30 diverging half-angles. Then, a series of computations are conducted to examine the efficiency of the use of a constant wall temperature as a function of the stagnation temperature in heat transfer calculations. The computations are performed for nominal stagnation pressure of 208 N/cm 2 and stagnation temperature of 539 K. The computed heat-transfer coefficients are compared to experimental data and a good agreement is found. A pronounced increase in the throat heat transfer coefficient peak is observed accompanied with a reduction in the contraction area ratio. Also, the peak of the heat transfer coefficient for the pipe inlet diameter of 7.8 cm is found to be 70% higher than the one related to the pipe of 16.51 cm diameter.

Numerical Investigation of Supersonic Flow Separation in Thrust-Optimized Contour Rocket Nozzle

“…A parallel implicit finite volume Fortran code based on full Navier-Stokes unsteady equations is developed to solve axisymmetric nozzle flows using RSM-Omega turbulence model, the numerical technic and validation via SST turbulence model is well described in reference Bensayah et al (2014).…”

Numerical Simulations of the Influence of Various Parameters on Heat Transfer and Flow Separation in Supersonic Cooled Nozzles

“…The research employed a conical nozzle contour presented in Fig. 1.b, which was identical to previous studies conducted by Bensayah et al (2014) and Cuffel et al (1968). The study applied prescribed total pressure and temperature at the inlet while maintaining axisymmetric conditions along the nozzle symmetry line.…”

Enhancement of Film Cooling Effectiveness in a Supersonic Nozzle

“…The efficiency and reliability of rocket engines have increased considerably over the past few decades. The continuously increasing demand for higher levels of propulsive thrust entails the need for operating the thrust chamber at significantly high levels of temperature, often exceeding 3000 K [ 1 ]. This necessitates that the thermal load on the internal walls of the rocket nozzle needs to be managed effectively in order to ensure the structural integrity of the system.…”