Investigation of the Effect of Cavitation in Nozzles With Different Length to Diameter Ratios on Atomization of a Liquid Jet

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Belkacem Abderrezzak ◽  
Yong Huang
Keyword(s):  
High Speed ◽  
Ambient Pressure ◽  
Complete Characterization ◽  
Test Facility ◽  
Liquid Jet ◽  
Complex Nature ◽  
Spray Structure ◽  
Wide Range ◽  
Orifice Flow ◽  
Atomization Characteristics

This study was conducted to investigate the effect of cavitation on liquid jet atomization characteristics in nozzles of different length to diameter (L/D) ratios. For this purpose, a spray test facility with an ambient pressure chamber was constructed, and sprays were recorded using a high-speed camera for a wide range of conditions, which provided complete characterization of the orifice flow fields and the emerging jet. Collapse length measurements are provided and indicate the complex nature of the nozzle flow. Extensive discharge coefficient measurements for each nozzle are also presented. Finally, the influence of the length to diameter ratio on cavitation and subsequently on the spray structure is also addressed.

Experimental Investigation on Flow and Breakup of Two-Dimensional Liquid Jets

2019 ◽  
Author(s):  
Amin Jaberi ◽  
Mehran Tadjfar
Keyword(s):  
High Speed ◽  
Volume Flow Rate ◽  
Quantitative Description ◽  
Sheet Thickness ◽  
Liquid Jets ◽  
Liquid Jet ◽  
High Speed Photography ◽  
Two Dimensional ◽  
Aspect Ratios ◽  
Wide Range

Abstract Studying of injectors with non-circular geometries has recently come to the spotlight of researchers as a potential technique to improve the liquid injection characteristics of different systems. In this work, the flow physics and breakup of two-dimensional liquid jets issued from flat slits into still air were experimentally investigated. Three injectors with aspect ratios of 30, 60 and 90 and thickness of 0.35 mm were manufactured to obtain two-dimensional liquid flow at the nozzle exit. The tests were performed for a wide range of volume flow rate, varying from 10 L/h to 240 L/h. Backlight shadowgraphy and high speed photography were employed to capture the flow dynamics of the jets. In order to capture every detail of the flow, photos of the liquid jet were taken from two views with 90° from each other. Using the visualizations, different regimes of the jet flow were explored and a regime map was proposed to distinguish these regimes based on the non-dimensional parameters of the liquid jet. Moreover, quantitative description of the main features of jet flows were obtained using an in-house image processing program. Measurements of different parameters including convergence length, maximum width, breakup length, sheet thickness to name a few, were conducted.

scholarly journals Test Facility for High-Speed Probe Calibration

2019 ◽  
Vol 213 ◽  
pp. 02033
Author(s):  
Tomáš Jelínek ◽  
Erik Flídr ◽  
Martin Němec ◽  
Jan Šimák
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Total Pressure ◽  
High Speed ◽  
Test Facility ◽  
Nozzle Outlet ◽  
Wide Range ◽  
Mach Numbers ◽  
Probe Calibration ◽  
Subsonic Nozzle

A new test facility was built up as a part of a closed-loop transonic wind tunnel in VZLU´s High-speed Aerodynamics Department. The wind tunnel is driven by a twelve stage radial compressor and Mach and Reynolds numbers can be changed by the compressor speed and by the total pressure in the wind tunnel loop by a set of vacuum pumps, respectively. The facility consists of an axisymmetric subsonic nozzle with an exit diameter de = 100 mm. The subsonic nozzle is designed for regimes up to M = 1 at the nozzle outlet. At the nozzle inlet there is a set of a honeycomb and screens to ensure the flow stream laminar at the outlet of the nozzle. The subsonic nozzle can be supplemented with a transonic slotted nozzle or a supersonic rigid nozzle for transonic and supersonic outlet Mach numbers. The probe is fixed in a probe manipulator situated downstream of the nozzle and it ensures a set of two perpendicular angles in a wide range (±90°). The outlet flow field was measured through in several axial distances downstream the subsonic nozzle outlet. The total pressure and static pressure was measured in the centreline and the total pressure distribution in the vertical and horizontal plane was measured as well. Total pressure fluctuations in the nozzle centreline were detected by a FRAP probe. From the initial flow measurement in a wide range of Mach numbers the best location for probe calibration was chosen. The flow field was found to be suitable for probe calibration.

The Design, Development and Evaluation of 3D Aerofoils for High Speed Axial Compressors: Part 1 — Test Facility, Instrumentation and Probe Traverse Mechanism

2005 ◽  
Author(s):  
D. Lippett ◽  
G. Woollatt ◽  
P. C. Ivey ◽  
P. Timmis ◽  
B. A. Charnley
Keyword(s):  
Collaborative Design ◽  
High Speed ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Test Facility ◽  
Mapping Technique ◽  
Efficiency Gain ◽  
Mapping Procedure ◽  
Tunnel Section ◽  
Wide Range

This paper, in two parts, reports measurements from, and simulation of, Cranfield University’s 3-stage high-speed axial compressor. Using this newly built rig, supported by European Commission, a consortium of gas-turbine companies have tested a set of conventionally stacked 2D rotor and stator blades. The results from this experiment were used to evaluate and assess the performance of several commercially available CFD codes leading to the collaborative design of an advanced three-dimensional blade set seeking, if possible, a 2% efficiency gain. The limited axial spacing between the measurement planes and the blade rows required the design of a unique seven probe assembly and traverse mechanism able to yaw and pitch the probes and to control the insertion depths. This mechanism was designed to accommodate different probes, such as cobra, fast response (pneumatic) and temperature measuring probes, and deliver area traverses between rotor and stators throughout the compressor. For probe calibration a high speed wind tunnel section was designed to accommodate this mechanism enabling calibrations for Mach numbers up to 0.78, as well as for a wide range of pitch and yaw angles values. This mechanism combined with a post processing programme incorporating a mapping technique for the relative offset of the measurement points on the probe secured very detailed results throughout the compressor. Measurements show the complex three dimensional flow structure and secondary flows associated with tip-leakage, endwall boundary layers, wake transportation and blade row interactions. The importance of a rigorous mapping procedure was particularly useful where the wake thickness was small and pressure gradients high in comparison to the probe size.

Hydrofoil Test Facility at ARL Penn State

2005 ◽  
Author(s):  
David R. Stinebring ◽  
William A. Straka ◽  
Steven M. Willits
Keyword(s):  
Test Section ◽  
High Speed ◽  
Full Range ◽  
Tip Vortex ◽  
Test Facility ◽  
Tunnel Wall ◽  
Vortex Interactions ◽  
Wide Range ◽  
Penn State ◽  
Primary Test

The two-dimensional test section of the ARL/Penn State 12-inch water tunnel has been modified to allow a wide range of dynamic tests using hydrofoils. Three examples of test configurations for the hydrofoil test facility are given. These include tests of a single conventional hydrofoil with non-sinusoidal deflections, tests with two hydrofoils for studying tip vortex interactions, and tests of base ventilated supercavitating hydrofoils. When testing a single hydrofoil, the angle of attack can be varied as a function of time using a cam drive system. Arc length Reynolds number of over 1 million based on a 1.5-inch chord are possible. Hydrofoil lift, drag and pitching moment can be measured during transient operation with and without cavitation. Tip vortex interaction studies have been performed by using a second hydrofoil mounted upstream of the primary test hydrofoil. This upstream hydrofoil is inclined to the tunnel wall so only the tip projects in front of the downstream hydrofoil. The upstream hydrofoil can be traversed across the test section to study the tip vortex interactions. Supercavitating hydrofoils have been tested by ventilating behind a wedge installed along the tunnel wall upstream of the hydrofoil. A full range of test instrumentation is used to support the studies, such as LDV, PIV, high speed video, and acoustic measurements.

Pressure Influence on the Flame Transfer Function of a Premixed Swirling Flame

2006 ◽  
Author(s):  
E. Freitag ◽  
H. Konle ◽  
M. Lauer ◽  
C. Hirsch ◽  
T. Sattelmayer
Keyword(s):  
High Pressure ◽  
Transfer Function ◽  
High Speed ◽  
Transfer Functions ◽  
Ambient Pressure ◽  
Operating Conditions ◽  
Phase Lag ◽  
Operating Pressure ◽  
Common Procedure ◽  
Wide Range

In order to assess the stability of gas turbine combustors measured flame transfer functions are frequently used in thermoacoustic network models. Although many combustion systems operate at high pressure, the measurement of flame transfer functions was essentially limited to atmospheric conditions in the past. With the test rig employed in the study presented in the paper transfer function measurements were made for a wide range of combustor pressures. The results show similarities of the amplitude response in the entire pressure range investigated. However, the increase of the pressure leads to a considerable amplitude gain at higher frequencies. In the low frequency regime the phase is also independent of pressure, whereas above this region the pressure increase results in a considerably smaller phase lag. These observations are particularly important when evaluating Rayleigh’s criterion: Interestingly, the choice of the operating pressure can render a system stable or unstable, so that the common procedure of applying flame transfer functions measured at ambient pressure for the high pressure engine case may not always be appropriate. The detailed analysis of high speed camera images, which were recorded to get locally resolved information on the flame response reveal different regions of activity within the flame that change in strength, size and location with changing operating conditions. The observed transfer function phase behavior is explained by the interaction of those regions and it is shown that the region of highest dynamic activity dominates the phase.

Atomization Characteristics of Thin Liquid Jet by High-speed Air Flow

2017 ◽  
Vol 2017.53 (0) ◽  
pp. 306
Author(s):  
Masatoshi DAIKOKU ◽  
Takumi YAMAGUCHI ◽  
Takahiro OKABE ◽  
Takao INAMURA ◽  
Tatsuya SOMA ◽  
...  
Keyword(s):  
High Speed ◽  
Air Flow ◽  
Liquid Jet ◽  
Atomization Characteristics

scholarly journals Low NOx LPP Combustion Test Facility With Four Transparent Windows for Non Intrusive Flow Diagnostics

1999 ◽  
Author(s):  
J. A. Alfaro ◽  
P. A. Rodríguez ◽  
A. Lecuona ◽  
R. Calle ◽  
B. Lázaro
Keyword(s):  
Gas Turbines ◽  
Single Point ◽  
Complete Characterization ◽  
Operating Conditions ◽  
Test Facility ◽  
Jet Engines ◽  
Wide Range ◽  
Measuring Techniques ◽  
The Individual ◽  
Transparent Windows

A high-pressure facility capable for testing Lean Premixed Pre-vaporized (LPP) combustor geometries is reported. The proposed design enables the use of both single-point and whole-field non-intrusive measuring techniques when the combustor operates under conditions representative of gas turbines or jet engines operation, thereby enabling the complete characterization of the turbulent flow field that develops inside LPP combustors. The individual control of the air and fuel supplies, provided, respectively, by a number of industrial compressors and a specific LPG supply facility, allows the investigation of a wide range of operating conditions. In this paper, the facility specifications are explained and adequately justified. Preliminary results are presented, showing the suitability of the design.

TESTING ON A HIGH SPEED ELECTRO-RHEOLOGICAL CLUTCH

1992 ◽  
Vol 06 (15n16) ◽  
pp. 2731-2747 ◽  
Author(s):  
A. R. JOHNSON ◽  
W. A. BULLOUGH ◽  
R. FIROOZIAN ◽  
A. HOSSEINI-SIANAKI ◽  
J. MAKIN ◽  
...  
Keyword(s):  
Shear Stress ◽  
High Speed ◽  
Test Facility ◽  
Initial Test ◽  
Quick Method ◽  
Magnetic Devices ◽  
Wide Range ◽  
Fluid Properties ◽  
Er Fluids ◽  
Er Fluid

The design of a prototype ER clutch and its associated test facility have been described and sample results from the initial test programme are presented. The ER clutch shows considerable promise and outperforms various magnetic devices. Further clutch and ER fluid developments should increase these advantages. The test facility described provides a quick method for obtaining a wide range of important fluid properties from a single small quantity of fluid in a single test facility operating under realistic engineering conditions. The results reported emphasize the need for continuing ER fluid development to increase the ER shear stress, to reduce the viscosity of the ER fluid, to reduce the electronic to ER shear stress time delay, and to improve the durability of ER fluids.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

NONLINEAR SIMULATION OF A HIGH-SPEED, VISCOUS LIQUID JET

1998 ◽  
Vol 8 (2) ◽  
pp. 155-178 ◽  
Author(s):  
J. H. Hilbing ◽  
Stephen D. Heister
Keyword(s):  
Viscous Liquid ◽  
High Speed ◽  
Liquid Jet ◽  
Nonlinear Simulation
Sign in / Sign up

Export Citation Format

Share Document