Performance Study on Flexible-Extendible Nozzle Based on Bidirectional Fluid-Solid Coupling Method

The effects of flight altitude and material elastic modulus on the performance of flexible-extendible nozzle are numerically studied to examine the nozzle altitude compensation ability. Analyses are conducted using bidirectional fluid-solid coupling method based on ANSYS platform. The simulations reveal that, with the increase of flight altitude, the flexible-extendible nozzle wall deformation aggravates. The nozzle inner flow takes on 'expansion-shock-expansion' wave pattern, the maximum deformation and maximum stress of the extendible section are amplified. With large elastic modulus (>100MPa), the deformation at the flexible section plays a minor role in changing the inner flow field. It is found that, at low altitude, the flexible-extendible nozzle has a significant higher specific impulse than that of the traditional nozzle; at high altitude, it has merely a little lower specific impulse than the traditional nozzle. An increase in the height-integrated specific impulse of 1.462% is reached for the present nozzle than the traditional nozzle at their design altitude of 6km. © 2021, Editorial Department of Journal of Propulsion Technology. All right reserved.