Numerical Prediction of liquid jet in cross flow using Ω-Y model

2014 ◽  
Author(s):  
Saravana Kumar ◽  
Konstantin A. Kurbatskii ◽  
Vivek Kumar
Keyword(s):  
Cross Flow ◽  
Numerical Prediction ◽  
Liquid Jet ◽  
Jet In Cross Flow

Pratt and Whitney Gas Turbine Combustor Design Using ANSYS Fluent and User Defined Functions

2012 ◽  
Author(s):  
Baris A. Sen ◽  
Yanhu Guo ◽  
Randal G. McKinney ◽  
Federico Montanari ◽  
Frederick C. Bedford
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cross Flow ◽  
Product Family ◽  
Liquid Jet ◽  
Resource Requirement ◽  
Ansys Fluent ◽  
Systematic Testing ◽  
Jet In Cross Flow ◽  
Break Up

This paper summarizes work conducted at Pratt & Whitney to incorporate ANSYS Fluent into the computational fluid dynamics-based combustor design process. As a first step, turbulence, combustion and spray models that already exist and have been validated in the Pratt & Whitney legacy computational fluid dynamics (CFD) solver ALLSTAR were converted into user defined functions (UDFs) for usage with the core ANSYS Fluent solver. In this manner, a baseline solver was established that allowed a systematic testing of the ANSYS Fluent native models. The baseline solver was validated against computational results as well as experimental data obtained for (i) liquid jet in cross-flow (LJICF), (ii) ambient spray injector tests and (iii) Pratt & Whitney next generation product family configurations. These test cases established a thorough evaluation of ANSYS Fluent with UDFs on a spectrum of simple to complex geometries and flow physics relevant to the conditions encountered in aeroengine combustors. Results show that Fluent produces calculated results obtained by ALLSTAR with similar level of agreement to the experiments. Furthermore, Fluent provides better convergence compared to the legacy ALLSTAR solver with a similar computational resource requirement. The ANSYS Fluent native spray break-up models were also tested for the liquid jet in cross flow configuration, demonstrating the importance of modeling the stripping and primary break-up regime of a spray jet. This capability is currently available only via the use of UDFs.

Liquid Jet in Cross Flow Modeling

2014 ◽  
Author(s):  
Jayanth Sekar ◽  
Arvind Rao ◽  
Sreedhar Pillutla ◽  
Allen Danis ◽  
Shih-Yang Hsieh
Keyword(s):  
Cross Flow ◽  
Liquid Jet ◽  
Flow Modeling ◽  
Gas Turbine Combustor ◽  
Two Phase ◽  
Droplet Distribution ◽  
Jet In Cross Flow ◽  
Jet Trajectory ◽  
Air Mixing ◽  
Secondary Breakup

All key combustor performance & operability characteristics like emissions, exit profile, durability, LBO etc. have a dependence on spray quality. Hence it is important to accurately predict spray characteristics for accurate combustor modeling. In this paper, a CFD based liquid jet in cross flow spray modeling approach adopted at GE Aviation is presented. Liquid jet in cross flow is a complex phenomenon that broadly involves jet trajectory evolution, surface breakup, column fracture and dispersion of secondary droplet particles. A two-phase steady state Volume of Fluid (VOF) approach is used to predict the liquid jet trajectory. A combination of output from VOF and empirical correlations (Sallam et. al; Oda et. al) is used to predict droplet distribution that includes diameter, velocity components and mass flow rate. Surface breakup is modeled by injecting droplets along the leeward surface of the liquid jet with spanwise perturbation to capture the transverse spread. Jet column breakup is modeled by injecting droplets including effects of unsteady fluctuations empirically to mimic the column fracture behavior. Discrete particles are then transported in a lagrangian frame coupled with secondary breakup of droplets. This approach has been validated on a benchmark quality dataset with an average SMD (Sauter Mean Diameter) error of ∼6 microns and is being used on Gas Turbine combustor fuel-air mixing devices employing liquid jet in cross flow atomizers.

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