Computation of flow field in an Air intake duct of LCA

A general purpose computer code called ' PHOENICS' has been used to compute flow field in an air intake duct geometry provided by ADA . Computations have .been carried out for both inviscid and viscous three-dimensional flows for a low subsonic uniform inlet Mach number of 0 .2 . The results have been presented in the form of static and total pressure contours and Mach number contours at different sections of the intake duct. They bring out the effect of the complex geometry of the duct on the flow

Design and evaluation of a controlled diffusion aerofoil blade for a LP compressor stator

A methodology based on geometric construction of CDA profiles and CFD flow simulation has been used to design a stator blade of a 3-stage LP compressor. The designed CDA blade is shown to13; perform better in terms of efficiency, pressure ratio and stall margin of the compressor compared to the original MCA blade

Viscous flow analysis in a convergent-divergent nozzle

The classical one-dimensional inviscid theory does not reveal the complex flow features in a choked CD nozzle accurately. The code Fluent has been used to compute RANS flow in a 2-D CD13; nozzle for nozzle pressure ratios (NPR) corresponding to presence of shock inside the diverging part of the13; nozzle. The computed solutions differ from the simple theory so far as shock location, shock structure and13; after-shocks are concerned

Numerical Simulation of Supersonic Combustion in a Slant Cavity

A commercial CFD code has been used to compute supersonic combustion in a slant cavity with upstream fuel injection. The 2-D steady state Reynolds Averaged Navier-Stokes equations along with RNG k-ε turbulence model have been solved. Combustion has been modeled by a 5-step 7-species reaction mechanism. The pressure-based algorithm, which the code uses, requires quite some adjustment of solution controlling options and boundary conditions for obtaining the solution. Experiences of using such algorithm for high speed flows are discussed in the paper. The converged solution, however, predicts the important flow features like separation shock ahead of fuel injection, bow shock near fuel injection, free shear layer across the cavity, flow recirculation inside the cavity, impingement of shear layer on slant wall and oblique shock at the trailing edge reasonably well

PARALLELIZATION OF A TURBOMACHINERY FLOW CODE ON NAL’S FLOSOLVER PARALLEL COMPUTER

A 3-D CFD flow code for multi-stage turbomachinery flow computation, namely the Dawes code ‘un_b3d_ke’ has been parallelized on the NAL Flosolver parallel computer Mk5 using MPI libraries. The parallelization has been effected employing very basic MPI subroutines. The parallel code performance has been tested for a high pressure ratio fan stage and a 3-stage compressor flow simulations and the results have been compared with the sequential code results. It is found that the time taken by the parallel code for the computation is substantially reduced

Theoretical Evaluation of H.P Turbine Blade profiel sections for GTX-35 VS Engine

High pressure turbine blade profile sections of GTX-35 VS engine were analysed by 2D-Euler code and a boundary layer code employing a (K- E) turbulence model . Computation was carried out to study velocity distribution on the profile surfaces and separation phenomenon for prescribed inlet free stream turbulence . The report presents the results of computation carried out on stator hub, mean and tip sections and rotor, hub and mean sections in detail

Computation of High Speed Cold Cavity Flow with a Commercial CFD Code

A commercial CFD code based on a pressure-based algorithm (SIMPLEC) has been used to compute high Mach number flow over a cavity, which has application in supersonic combustors. The difficulties encountered in obtaining converged solution for compressible flow by the pressure-based method are discussed. The predicted solution is compared with the available experimental results. Though some quantitative differences exist between them, the qualitative agreement is generally good

Prediction of liquid film cooling in presence of wall heat flux 13; 13;

The numerical procedure of Shembharkar and Pai (1985) for predicting film cooling with a liquid coolant was extended to take into account significant heat flux through the wall and was used to analyze the film-cooling process with an air-water system. The method solves the conservation equations of mass, momentum, species, and enthalpy for the gaseous phase within the framework of a two-dimensional turbulent flow approximation and the equations for the liquid phase through a one-dimensional laminar flow formulation, with appropriate matching at the gas-liquid interface. The method provides a solution for the flow and thermal fields, both in the region where the liquid exists as a subcooled film and in the region where it is completely vaporized. The results indicate that the freestream velocity and temperature have significant effects on the film-cooled length. In the absence of a wall heat flux, the film remains subcooled over distances encountered in practice, whereas in the presence of a wall heat flux, the procedure predicts the reduction in the film-cooled length due to the increase in interface temperature, concentration, and evaporation rate. (I.S.

Prediction of film cooling with a liquid coolant

A numerical method of analyzing film cooling with a liquid coolant is presented. The model assumes a turbulent boundary-layer flow for the hot gas stream and a Couette flow in the liquid coolant film. A marching procedure is employed for solution of the equations of mass, momentum, enthalpy and species conservation. Numerical results for an air-water system are presented. The effects of flow conditions on the film cooling mechanism are discussed

CFD Analysis of a high pressure ratio fan stage

A high pressure ratio fan stage, designed under NAL-CAE collaborative programme, has been subjected to 3-D CFD flow analysis using a turbomachinery flow code called Dawes code. Computations have been carried out for three speeds namely 100%, 60% and 50% design speed. For each speed, seven to ten points have been obtained on the performance curves. The flow details have been studied with the help of Mach number contour plots and velocity vector plots. The present computed results at the design speed are also compared with the results from another CFD analysis carried out at BUAA (China) for the same fan stage. Computations at the off-design speeds of 60% and 50% are compared with the experimental dat