Estimating Spray Characteristics of the Air-Blast atomizer of a Typical Jet Engine using Definition of the New Non-dimensional Number K: Numerical and Experimental Study

Abstract

In this paper, by using a numerical solution and experiment investigation, a non-dimensional number is introduced to estimate the characteristics of a real engine airblast atomizer spray. This type of atomizers is usually used in airplain engines. The test is conducted in ambient atmospheric pressure and at 300 K temperature and the effects of pressure on atomizer flow rate and spray con angle are investigated. We used the discrete phase model and real information of the ALF502 engine for simulations and for boundary conditions respectively. Since the main application of this airblast atomizer is in aircraft engines and in the real working conditions, none of the pressure and flow rate parameters is constant, thus, the main aim of this research is to define a nondimensional number K, which considers the effects of working liquid flow rate, air flow rate and pressure on the droplets average diameter and spray con angle simultaneously. The results showed that, in general, with the increase of non-dimensional K number, the average diameter of droplets in primary and secondary break up increases, but spray con angle decreases. Furthermore, numerical solution results are compared with experiment results and 9.98% error was observed.

Keywords

• airblast atomizer
• droplet average diameter
• non-dimensional number K
• spray cone angle