Theoretical and experimental studies on the coefficient of discharge and spray cone angle of a swirl spray pressure nozzle using a power-law non-Newtonian fluid

1983 ◽  
Vol 12 (1) ◽  
pp. 39-68 ◽  
Author(s):  
S.K. Som
Keyword(s):  
Newtonian Fluid ◽  
Power Law ◽  
Cone Angle ◽  
Experimental Studies ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Coefficient Of Discharge ◽  
Pressure Nozzle

scholarly journals Modeling of Non-Newtonian Fluid Flow Within Simplex Atomizers

2010 ◽  
Author(s):  
Mohammad Rezaeimoghaddam ◽  
Rasool Elahi ◽  
M. R. Modarres Razavi ◽  
Mohammad B. Ayani
Keyword(s):  
Fluid Flow ◽  
Newtonian Fluid ◽  
Power Law ◽  
Stokes Equations ◽  
Cone Angle ◽  
Navier Stokes ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Navier Stokes Equations ◽  
Pressure Swirl

In this paper the Volume-of-Fluid (VOF) method is used to simulate Newtonian and non-Newtonian fluid flow within simplex (pressure-swirl) atomizers. The two-dimensional axisymmetric swirl Navier-Stokes equations coupled with the VOF method is employed for accounting the formation mechanism of the liquid film inside the swirl chamber and the orifice hole of the pressure swirl atomizer. For verification of the code, the numerical results were compared with experimental data for large scale prototype injector with water (Newtonian fluid) as injection fluid in various constant inlet mass flow rate. By using power-law equation to calculate shear stress terms in the Navier-Stokes equations, the code is extended to compute Newtonian and non-Newtonian fluid flow inside the atomizer. The time-independent purely viscous power-law fluids flow in pressure-swirl atomizers is simulated. The effects of shear-thinning fluids (0.5 < n <1), viscous Newtonian (n = 1) fluids and shear thickening fluids (1< n < 1.5) on atomizers performance (discharge coefficient and spray cone angle) were investigated. Results were shown that with increasing the power-law index the spray cone angle decreases and the discharge coefficient increases.

scholarly journals Effect of Inlet Tangential Port Area on the Performance of Small – Scale Simplex Atomizer

2012 ◽  
Author(s):  
Selvan G. Muthu ◽  
H. S. Muralidhara ◽  
Vinod Kumar Vyas ◽  
Kanth T. P. Dinesh ◽  
S. Kumaran ◽  
...  
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Cone Angle ◽  
Droplet Size Distribution ◽  
Small Scale ◽  
Sauter Mean Diameter ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Mean Diameter ◽  
Coefficient Of Discharge

An experimental investigation was conducted to study the effects of increased area of inlet tangential ports on the performance of small scale simplex atomizer. The spray characteristics of three different simplex atomizer representing increasing area of inlet tangential ports are examined using water as a working fluid. Measurements of coefficient of discharge, spray cone angle, Sauter mean diameter and droplet size distribution were carried out over wide range of injection pressure. Coriolis mass flow meter was used to measure coefficient of discharge. Spray cone angle was measured by image processing technique. Sauter mean diameter and droplet size distributions were measured by Malvern droplet sizing instrument. It was observed that with increase in area of inlet tangential ports the size of air core produced along the center line reduced, which increases the coefficient of discharge. Spray cone angle decreases with increase in area of inlet tangential ports. It was found that increase in area of inlet tangential ports reduces swirl strength inside swirl chamber, which results in increasing Sauter mean diameter. Better droplet size distribution was observed for lower area of inlet tangential port configuration. The obtained experimental results were compared with experimental correlations available in literatures. Deviations in the obtained experimental results and experimental correlations was observed. This is due to difference in the size of atomizer used and difference in experimental techniques used between the present work and other investigations.

scholarly journals Experimental Studies on the Spraying Pattern of a Swirl Nozzle for Coal Dust Control

2018 ◽  
Vol 8 (10) ◽  
pp. 1770 ◽  
Author(s):  
Guijun Gao ◽  
Changjiang Wang ◽  
Ziming Kou
Keyword(s):  
High Speed ◽  
Coal Dust ◽  
Cone Angle ◽  
Experimental Studies ◽  
Dust Control ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Particle Size Analyzer ◽  
Atomization Mechanism ◽  
And Performance

The experimental and numerical studies were performed to understand the atomization mechanism of pressure spray of a swirl nozzle. The design and performance parameters such as spray cone angle, velocity of particles, spray pressure, and Sauter Mean Diameter (SMD) of the droplets were studied using a laser particle size analyzer and high-speed camera. The results show that the SMD increases at first, then decreases as the spray distance increases, and finally tends to be stable after 1 m. The SMD is largest in the center of the spray field and decreases gradually along the radial direction. The SMD distribution is more concentrated near the nozzle. Increasing spray pressure and deceasing nozzle diameter both can make the SMD distribution more concentrated and uniform. The swirl nozzle has been used in a coal mine and was shown to be very effective in suppressing coal dust compared to other traditional nozzles.

Method of Identifying Injector Coking From the Spray Field of Mechanical and CRDi Injectors Using Intensity of Scattered Light

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Ronith Stanly ◽  
Gopakumar Parameswaran ◽  
Bibin Sagaram
Keyword(s):  
Scattered Light ◽  
Near Field ◽  
Cone Angle ◽  
Angle Measurement ◽  
Field Region ◽  
Fuel System ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Cleaning Procedure ◽  
Spray Field

The influence of injector coking deposits on the spray field of single-hole mechanical port fuel injectors and multihole common rail direct injection (CRDi) injectors was studied using light scattering technique coupled with image processing and analysis. Instead of employing the traditional accelerated coking process to study injector spray field deterioration, in-service injectors were selected and cleaned using a commercial fuel system cleaning procedure. Variation in atomization characteristics of coked and cleaned injectors were observed based on the spatial distribution of fine, medium, and coarse droplets in the near-field region of the injector spray zone and analyzed as a function of the intensity of scattered light. The improvement in the atomization perceived by this method was compared with traditional techniques like spray cone angle measurement, speed characterization of spray jets, and weight reduction of injector nozzles and needles. It was observed that after the fuel system cleaning procedure, a reduction in the number of coarse droplets in the near-field region and an increase in the number of medium and finely sized droplets was observed, suggesting better atomization of fuel in the near field spray zone.

Experimental and Numerical Studies of Diesel Spray Evaporation and Combustion in a Gas Turbine Matrix Burner

2009 ◽  
Author(s):  
Dieter Bohn ◽  
James F. Willie ◽  
Nils Ohlendorf
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Instability ◽  
Cone Angle ◽  
Spray Angle ◽  
Test Rig ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Flow Simulations ◽  
Air Inlet

Lean gas turbine combustion instability and control is currently a subject of interest for many researchers. The motivation for running gas turbines lean is to reduce NOx emissions. For this reason gas turbine combustors are being design using the Lean Premixed Prevaporized (LPP) concept. In this concept, the liquid fuel must first be atomized, vaporized and thoroughly premixed with the oxidizer before it enters the combustion chamber. One problem that is associated with running gas turbines lean and premixed is that they are prone to combustion instability. The matrix burner test rig at the Institute of Steam and Gas Turbines at the RWTH Aachen University is no exception. This matrix burner is suitable for simulating the conditions prevailing in stationary gas turbines. Till now this burner could handle only gaseous fuel injection. It is important for gas turbines in operation to be able to handle both gaseous and liquid fuels though. This paper reports the modification of this test rig in order for it to be able to handle both gaseous and liquid primary fuels. Many design issues like the number and position of injectors, the spray angle, nozzle type, droplet size distribution, etc. were considered. Starting with the determination of the spray cone angle from measurements, CFD was used in the initial design to determine the optimum position and number of injectors from cold flow simulations. This was followed by hot flow simulations to determine the dynamic behavior of the flame first without any forcing at the air inlet and with forcing at the air inlet. The effect of the forcing on the atomization is determined and discussed.

Effects of Fuel Nozzle Condition on Gas Turbine Combustion Chamber Exit Temperature Distributions

2010 ◽  
Author(s):  
Kristen Bishop ◽  
William Allan
Keyword(s):  
Combustion Chamber ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Operating Conditions ◽  
Spray Cone Angle ◽  
Mixing Processes ◽  
Spray Cone ◽  
Temperature Distributions ◽  
Fuel Nozzle ◽  
Exit Temperature

The effects of fuel nozzle condition on the temperature distributions experienced by the nozzle guide vanes have been investigated using an optical patternator. Average spray cone angle, symmetry, and fuel streaks were quantified. An ambient pressure and temperature combustion chamber test rig was used to capture exit temperature distributions and to determine the pattern factor. The rig tests matched representative engine operating conditions by matching Mach number, equivalence ratio, and fuel droplet size. It was observed that very small deviations (± 10° in spray cone angle) from a nominal distribution in the fuel nozzle spray pattern correlated to increases in pattern factor, apparently due to a degradation of mixing processes, which created larger regions of very high temperature core flow and smaller regions of cooler temperatures within the combustion chamber exit plane. The spray cone angle had the most measureable influence while the effects of spray roundness and streak intensity had slightly less influence. Comparisons were made with published studies conducted on the combustion chamber geometry, and recommendations were made for fuel nozzle inspections.

scholarly journals Experimental Study of Spray Characteristics of Kerosene-Ethanol Blends from a Pressure-Swirl Nozzle

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tao Zhang ◽  
Bo Dong ◽  
Xun Zhou ◽  
Linan Guan ◽  
Weizhong Li ◽  
...  
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Ethanol Blends ◽  
Pressure Swirl ◽  
Spray Velocity

Partial replacement of kerosene by ethanol in a gas turbine is regarded as a good way to improve the spray quality and reduce the fossil energy consumption. The present work is aimed at studying the spray characteristics of kerosene-ethanol blends discharging from a pressure-swirl nozzle. The spray cone angle, discharge coefficient, breakup length, and velocity distribution are obtained by particle image velocimetry, while droplet size is acquired by particle/droplet imaging analysis. Kerosene, E10 (10% ethanol, 90% kerosene), E20 (20% ethanol, 80% kerosene), and E30 (30% ethanol, 70% kerosene) have been considered under the injection pressure of 0.1–1 MPa. The results show that as injection pressure is increased, the discharge coefficient and breakup length decrease, while the spray cone angle, drop size, and spray velocity increase. Meanwhile, the drop size decreases and the spray velocity increases with ethanol concentration when the injection pressure is lower than 0.8 MPa. However, the spray characteristics are not affected obviously by the ethanol concentration when the injection pressure exceeds 0.8 MPa. A relation to breakup length for kerosene-ethanol blends is obtained. The findings demonstrate that the adding of ethanol into kerosene can promote atomization performance.

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