Characterization of Splash-Plate Atomizers Using Numerical Simulations

Abstract

A computational model has been developed that can be used for the spray characterization of splash-plate atomizers. The computer model, called BLSpray, can accurately simulate the impingement of a liquid jet on the surface of a splashplate nozzle, as well as the formation of the liquid film and subsequent droplets. To validate the model, simulation results were compared to experimental measurements for the film thickness and velocity distributions in a typical splash-plate nozzle. Close agreement between numerical results and measurements validated the model and its underlying assumptions. Correlations were developed between liquid film characteristics at the nozzle exit and the spray mean drop sizes. This was done by running many different numerical simulations on a typical splashplate nozzle using the developed computer code. The correlations were obtained by performing a close inspection of the numerical results in order to extract all information regarding the liquid film and spray. The results of the developed code were combined with the correlations to get the spray drop size distribution in a more practical approach, with less computational time and effort. This capability, along with the program module developed for analyzing the output data, has turned the developed code into an efficient and practical tool in the design and characterization of splash-plate nozzles. The developed computer model can be used to predict the behavior of a flow into a nozzle at different operating conditions, and also as a tool in the design of new nozzles. This paper presents mathematical formulations, results of model validation, and the spray drop size distribution for a typical ALSTOM splash-plate nozzle. Also, the effect of some of the main parameters on the spray pattern, such as nozzle diameter, nozzle angle, and nozzle velocity, are investigated.

Numerical modelling of mirror nozzle flow

“…However, to our knowledge, few specific works focused on the relationship between nozzle geometry parameters and the produced spray. The numerical studies realized on black liquor nozzles provided promising results for nozzle design [4].…”

Dynamics of a thin radial liquid flow

“…Spray formation by fire sprinkler [4,5,6] or plate nozzle [7,8,9] involves a liq-5 uid film as the first step of a spray formation. The governing parameters of the spray formation process are the thickness and the velocity of the liquid layer.…”

Equipment for printing of high viscosity liquids and molten metals

“…The impact can be visualised by two cameras using stroboscopic illumination to view both the impact as well as the exit point. To generate the liquid screen, a splash plate nozzle type is used where a jet impinges on the splash plate, resulting in a small but stable fluid screen, with a thickness which can be set to be in the same order as the droplet diameters used [72,73]. …”