CFD Analysis and Parameter Optimization of Co...

CFD Analysis and Parameter Optimization of Convergent Divergent Nozzle

Author Name : Mr. Aniket Dhanraj Bhagat

ABSTRACT

In this research paper the 2D numerical analysis of convergent divergent nozzle (CD-Nozzle) is studied for parameter optimization. Nozzles are the integrated part of the gas turbine engine which expand the hot gases from the low pressure (LP) turbine and generate the thrust. CD nozzles are used to get supersonic flow at outlet by expansion and the main condition to achieve through CD nozzle is chocking of nozzle throat. The current research work is expounded to the computational fluid dynamic analysis of two-dimensional convergent-divergent nozzle in Ansys software. It uses the CVM (control volume method) to solve the RANS (Reynolds Average Navier Stokes Equation) of fluid flow problem formulated under the given boundary condition. The basic aim of the current study is to identify the most suitable or optimum configuration of convergent-divergent angle in DC Nozzle which increases the critical pressure ratio and reduces the pressure drop across the CD nozzle. The angle of convergent cone and divergent cone are change accordingly to study the effect of geometry variation on nozzle flow. The parameter of a nozzle is taken according to the CD nozzle geometry. The different configuration has made by vary angle from 13 to 38 degree at the interval of 5 degrees for Convergent angle (α) and for divergent angle (β), it varies from 13 degrees to 23 degrees at the interval of 3 degrees. The numerical solution of this problem was analyzed in the ANSYS FLUENT. The boundary condition is gauge total pressure and temperature 300K at inlet and pressure outlet. The output data is obtained by post-processing the data in fluent in the form of pressure distribution and velocity variation also the Mach number are calculated for each combination. To see the effect of changing the variation of throat area simulation is performed for 3 cases that is length of throat is varied from 90 mm to 110 mm at 10 mm interval keeping convergent and divergent cone angle 15 degrees and 12.5 degrees. The effect of selection of the turbulence model is also studied by using two different turbulence models namely SST K-ω and K-ε models.

Keywords- Convergent-Divergent Nozzle, CFD Simulation, Variation in Meshing, Structural Meshing, Wall Pressure, Mach No, Turbulence Models, De Laval Nozzle.