Importance of Geometrical Factors on Spray Characteristics of Spill-Return Atomizers

Abstract

An experimental investigation into small pressure-swirl spill-return atomizers was made to determine the effect of the entry port number, swirl-chamber shape, spill-line design, and the manufacturing precision on the spray quality and stability. The atomizers were studied using phase-Doppler anemometry, high-speed visualization, and mechanical patternation. Jet A-1 fuel was sprayed at inlet pressures of 0.5, 1.0, and 1.5 MPa and for spill-to-feed ratios of 0, 0.4, and 0.8. The chamber shape influenced the spray characteristics of the simplex atomizers only moderately with no systematic effect of conical chambers to the others. The spray was found to be circumferentially heterogeneous; its uniformity improved with increase in the pressure, while the effect of swirling port number was negligible. Atomizers with axial spill orifice demonstrated strong spray pulsations at a spill-to-feed ratio of zero. A periodic decay of the air core was identified as a possible reason for the pulsations. Atomizers with off-axis spill orifices always produced a stable spray. Atomizers with tangential inlet ports provided a finer spray than those with helical ports. Manufacturing precision, axial symmetry, and matching of the surfaces of connected parts were found important for the spray symmetry and homogeneity.

High-speed 3D imaging of liquid sheet surfaces using the FP-LIF technique

“…The liquid was injected at ambient temperature and pressure condition (around 20 • C and atmospheric pressure) using a pressure swirl atomizer. The atomizer is a 10× scaled up version of an atomizer developed for an aircraft engine produced in transparent plexiglass [14]. The atomizer scaling and transparency allows detailed optical measurement of the internal flow as well as the liquid sheet formation.…”

Testing the effect of new constructions of swirl insert on the parameters of spray

“…The construction of an atomizer has a direct impact on its effectiveness and efficiency. Over the last few decades, there have been significant changes in their design, which in turn have allowed for improvements in their performance and reliability (Gad et al, 2022;Jedelský et al, 2021). In the era of technological progress and improvements of process equipment, modifications to the design of atomizers are an extremely important issue.…”

Numerical and experimental analysis on spray characteristics of biodiesel (waste cooking oil) using pressure swirl atomizer

“…With the energy gained from pressure, fuel droplets can achieve higher velocity than surrounding gas. It can create centrifugal force, which facilitates a swirl motion and spreading liquid forms conical sheet at the exit from orifice 24,25 . Spray characteristics of fuel are highly influenced by injection and ambient pressure.…”

“…It can create centrifugal force, which facilitates a swirl motion and spreading liquid forms conical sheet at the exit from orifice. 24,25 Spray characteristics of fuel are highly influenced by injection and ambient pressure. Droplet velocity, cone angle, and SMD are important parameters of pressure swirl nozzle, which reflects transport, distribution, and drop generation in combustion chamber respectively.…”