An integrated and fast methodology for thermal load prediction of rocket nozzle based on the coupled inviscid-viscous method

Fast and accurate thermal load prediction is an essential perquisite for efficient design and optimization of nozzle thermal protection system. In order to achieve the balance between accuracy and efficiency in thermal load prediction of rocket nozzle, an integrated and fast methodology based on the coupled inviscid-viscous method is developed, providing a technical basis for the development of thermal load prediction and thermal protection system design tools for rocket nozzle under service environment. Nozzle geometry design, grid generation and flow field computation modules are systematically integrated in a dedicated computational tool, avoiding tedious steps in different software tools as in traditional computational fluid dynamic (CFD) method. Verification and validation of this methodology is completed through typical cases, and comparisons with the results of traditional CFD method and empirical engineering formula show that accuracy of this methodology is comparable to traditional CFD method, and much better than empirical engineering formula. In terms of computation efficiency, local time-stepping, implicit residual smoothing, preconditioning for low Mach numbers and OpenMP parallel framework are incorporated to accelerate the most time-consuming process of solving the inviscid flow field, and the total time of applying this methodology from nozzle geometry design to thermal load prediction is less than 10 seconds for typical 2D nozzle cases.