Study of Factors Influencing the Thrust Response of Convergent Nozzle Block

Nayyer Nayab Malik ； M.Javed Hyder

《中國機械工程學刊》 42卷1期 (2021/02) Pp. 121-130

摘要

This paper investigates the effect of different parameters on thrust response of convergent nozzle block. Computational Fluid Dynamics (CFD) based simulations have been carried out and the results are experimentally verified through model testing setup. The scope of this research is to develop understanding about the thrust generation phenomenon by single/multi- nozzle blocks and to utilize this knowledge in related applications. Convergent nozzles are usually employed in air jet propulsion system where it is used as thruster providing sufficient reaction force for lifting platform. It is therefore required to select and design a nozzle that can displace more nearby air with a steady flow to get the stable thrust output. CFD analysis has been done on convergent nozzle block's to determine the optimal fluid dynamic parameters and for studying the effect of flow characteristics on thrust output. For the simulations, ANSYS Fluent has been used as software platform. The density based solver has been adopted with utilization of k-ω SST transport model equation. Structured mesh is applied on the nozzle domain to get precise and consistent results. Optimal solution is obtained by achieving mesh grid independency based on y^+ criterion, reducing the simulation time. It is established that high area ratio, high inlet pressure, longer converging length of nozzle with S3 shape gives the higher thrust value while increasing the number of nozzles in a block provides stable fluid flow with greater thrust per unit.

關鍵字

Convergent Nozzle block ； Optimal Thrust ； CFD Analysis ； Isentropic Flow ； ANSYS Fluent