Gas Flow and Ablation of 122 mm Supersonic Rocket Nozzle Investigated by Conjugate Heat Transfer Analysis

Abstract

The propellant gas flow of a supersonic rocket in inappropriate operating conditions can cause excessive ablation inside a nozzle. In this research, conjugate heat transfer analysis (CHTA), consisting of computational fluid dynamics (CFD) and finite element analysis (FEA), was applied to investigate the gas flow and ablation of a 122 mm nozzle as a case study in the transient state, based on actual operating conditions. First, the nozzle was tested in a static experiment. Then, the experimental results were employed for CHTA settings and validation. Next, after completing the CFD calculation, the results revealed that the nozzle’s gas flow, temperature, pressure, Mach number, shock, etc. were consistent with theoretical results. Finally, using the CFD results as loads, the FEA results showed the equivalent von Mises stress (sv), which was consistent with the ablation results from the experiment, as expected. The more the sv, the greater the ablation. Both sv and ablation were high near the throat and decreased further away. In addition, increasing the insulators’ thickness reduced sv, leading to ablation reduction. The research findings contribute to an understanding of ablation and the methodology of employing CHTA to improve the design of 122 mm and other nozzles with reduced ablation for higher efficacy.

CFD Analysis of De Laval Nozzle of a Hybrid Rocket Engine

“…Many studies employed CFD software to design and analyse CD nozzles [3][4][5][6]. Due to its accuracy when compared to theory, CFD has recently been used in more investigations on nozzle flow [7][8][9][10][11][12][13][14][15].…”

CFD—Assisted Expert System for N2-Controlled Atmosphere Process of Rice Storage Silos

“…The CFD is a computer simulation to solve fluid flow, fluid-fluid, fluid-solid, or fluidgas interaction problems using a numerical method based on the Navier-Strokes equations. For example, related to ventilation and airflow [15][16][17][18][19], CFD was employed to determine the ventilation and successfully develop technology and architectural design techniques [15], investigated the airborne transmission for medical and healthcare purposes [16], studied O 3 gas flow through a mass of rice grain and simulated of the O 3 gas injection in a sio with rice grain to control S. zeamais [17], designed a novel ultrasonic cleaning tank for jewellery factories [18], and investigated gas flow and ablation of a supersonic rocket nozzle to enhance the performance in missions [19]. All the mentioned works [15][16][17][18][19] confirm that CFD can simulate fluid flow in complex environments and provide accurate simulation results consistent with actual situations; therefore, CFD suits this research.…”

“…In addition, D i,m is the species' mass diffusion coefficient in the mixture i, D T,i is the thermal (Soret) diffusion coefficient, µ t is the turbulent viscosity, and Sc t is the turbulent Schmidt number. The equations' complete forms of conservation and k-ε turbulence equations are reported in references [18,19,22], respectively. Importantly, the k-ε turbulence model was applied in this work since it is suitable for the gas flow behaviour in silos and provides reliable CFD results under limited computational resources.…”

“…The smallest mesh size is in the inlet and outlet. Fluent meshing with polyhedrons can increase the number of nodes and elements in some regions by automatically transforming element shapes and resizing in the model to automatically acquire accurate simulation results [24,25], which is more convenient and effective than mesh-independent analysis as employed in [18,19]. • Ventilation setting Figure 8 presents the ventilation setting.…”