Computational Model to Predict Flow in Simplex Fuel Atomizer

Abstract

This paper presents a computational analysis of flow in simplex fuel atomizers using Arbitrary-LagrangianEulerian method. It is well established that the geometry of an atomizer plays an important role in governing its performance. In this paper, we have investigated the effect on atomizer performance of four geometric parameters, viz., inlet slot angle, spin chamber convergence angle, trumpet angle and trumpet length. For constant mass flow rate through the atomizer, the effects on atomizer performance are shown in terms of variations of dimensionless film thickness, spray cone half angle, and discharge coefficient. Results indicate that increase in inlet slot angle results in lower film thickness and discharge coefficient and higher spray cone angle. The spin chamber converge angle has an opposite effect on performance parameters, with film thickness and discharge coefficient increasing and the spray cone angle decreasing with increasing convergence angle. For a fixed trumpet length, the trumpet angle has very little influence on discharge coefficient. However, the film thickness decreases and spray cone angle increases with increasing trumpet angle. For a fixed trumpet angle, the discharge coefficient is insensitive to trumpet length. Both the spray cone angle and the film thickness are found to decrease with trumpet length. The geometric parameters considered in this study have not been addressed in available semi-empirical correlations and as such the present correlations do not provide guidance about these parameters to atomizer designers. It is seen that our computational code is able to predict influence of these geometric parameters on the atomizer performance well and can act as a very useful design tool for simplex atomizers.