Effects of Efflux Velocity and Buoyancy on Fuel Jets

2014 ◽  
Vol 41 (5) ◽  
pp. 430-439
Author(s):  
Mohammed A. Azim
Keyword(s):  
Efflux Velocity

Design Aspects of Power Plants for V/STOL Aircraft

1967 ◽  
Author(s):  
J. F. Coplin
Keyword(s):  
Power Plants ◽  
Weight Ratio ◽  
Gas Generator ◽  
Extensive Experience ◽  
Thrust Vectoring ◽  
Two Generations ◽  
High Integrity ◽  
Integrated Concept ◽  
High Thrust ◽  
Efflux Velocity

Thrust in execess of that required for cruise and flight maneuvering is necessary to provide an aircraft with a VTOL capability. The extra thrust may be obtained by enlarged cruise engines with thrust vectoring or by retaining the optimum-size cruise engine possibly with thrust vectoring and adding a lift power plant in the form of lift jets or lift fans. A brief outline of extensive experience with lift jets, thrust vectoring, and lift fans is given and the importance of this background in making it possible to design more advanced engines which will satisfactorily meet practical operational requirements is brought out. Experience in two generations of lift-jet flight testing has shown many important areas where specal features must be incorporated in the design from the beginning to achieve high thrust for a compact volume, light weight, and high integrity in the relatively severe environment in which the lift jet has to operate. Examples are cited. The relative importance of thrust/volume and thrust/weight ratio is shown with reference to VTOL strike and transport aircraft. An integrated concept, using compact lift jets for VTOL strike aircraft and compact low-efflux-velocity lift fans using the same engine as a gas generator, is briefly noted.

scholarly journals Novel energy coefficient used to predict efflux velocity of tidal current turbine

Energy ◽  
2018 ◽  
Vol 158 ◽  
pp. 730-745 ◽  
Author(s):  
Shuguang Wang ◽  
Wei-Haur Lam ◽  
Yonggang Cui ◽  
Tianming Zhang ◽  
Jinxin Jiang ◽  
...  
Keyword(s):  
Tidal Current ◽  
Energy Coefficient ◽  
Tidal Current Turbine ◽  
Current Turbine ◽  
Efflux Velocity

An Experimental and Computational Investigation on the Pre-Heating of Fuel to Improve Cold Starting of Diesel Engines

2003 ◽  
Author(s):  
Gurpreet S. Gambhir ◽  
Duane L. Abata ◽  
Donna J. Michalek
Keyword(s):  
Ambient Air ◽  
Computational Investigation ◽  
Fuel Temperature ◽  
Sauter Mean Diameter ◽  
Ambient Temperatures ◽  
Cold Starting ◽  
Compression Ignition Engines ◽  
Cold Room ◽  
Physical Phenomena ◽  
Efflux Velocity

This paper describes the effect of elevated fuel temperature on cold starting operability in compression ignition engines. This study was based on the hypothesis that in a cold start condition, fuel heated to a temperature higher than the surrounding ambient air before it enters the combustion chamber would improve cold starting. Experiments on heating the injector and the fuel before the injection event were performed in a cold room facility with ambient temperatures varying from −20 degrees to 20 degrees Celsius. A computational analysis of the injector was conducted using Star-CD to more fully understand the physical phenomena involved and help explain results obtained from the experiment. Results indicated that fuel heating does affect the efflux velocity, Sauter mean diameter and the lifetime of a fuel droplet. Droplet break-up time and spray penetration are not much affected. Computational and experimental results were within 30% of each other. Results of this work should be useful in the design of improved cold starting methods of diesel fueled engines.

Optimal Configuration Selection Through Experimental Tests on Branched Heat Exchanger With R134 Organic Fluid

2019 ◽  
Author(s):  
Roberto Capata ◽  
Alfonso Calabria
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Test Bench ◽  
Experimental Tests ◽  
Constructal Theory ◽  
Detailed Knowledge ◽  
Nusselt Numbers ◽  
Configuration Selection ◽  
Efflux Velocity ◽  
Made In

Abstract The aim of this work the analysis of compact branched heat exchangers, by measuring thermal efficiency and the pressure drop in several experimental tests. Three different heat exchanger configuration have been considered. In the first device, the constant efflux velocity, in the internal channels, was imposed. The second exchanger was realized by imposing constant the value of the Reynolds number. The last device was created according to the instructions of the constructal theory. All three exchangers are aluminum made. In addition, in order to have a more detailed knowledge of the phenomenon and to identify what are the parameters that govern heat transfer, an organic fluid has been used and tested. In our case R1234 organic fluid. It was therefore necessary to realize an appropriate test bench for the use of the organic fluid. Once realized, several tests were conducted. Finally in order to be able to indicate which configuration results the optimal one, the Prandtl and Nusselt numbers were obtained and compared.

Jet diffusion in the region of flow establishment

1967 ◽  
Vol 27 (2) ◽  
pp. 231-252 ◽  
Author(s):  
Sedat Sami ◽  
Thomas Carmody ◽  
Hunter Rouse
Keyword(s):  
Static Pressure ◽  
Differential Forms ◽  
Turbulent Shear ◽  
Pressure Probe ◽  
Mean Flow ◽  
Fluctuating Pressure ◽  
Air Jet ◽  
Intermittency Factor ◽  
Energy Equations ◽  
Efflux Velocity

In the flow-establishment region of an air jet issuing with an efflux velocity of about 35 ft./sec from a 1.0 ft. diameter nozzle into still air, measurements were made of mean axial and radial velocities, mean static pressure, turbulence intensities, turbulent shear, and pressure fluctuation. For the measurement of the latter a pressure probe using a ceramic piezo-electric tube was developed. Also included in the measurements were the temporal mean gradient and autocorrelation of the axial-velocity fluctuation and the intermittency factor. The fluctuating-pressure and turbulence-intensity fields were observed to be closely similar in form. Through use of the measured distributions of mean-flow and turbulence characteristics, all terms of the integral and differential forms of the momentum and mean-energy equations were evaluated throughout the region. The results are presented herein by curves of variation of each of the terms as they appear in the corresponding equations.

Determination of the efflux velocity from a ship's propeller

2004 ◽  
Vol 157 (2) ◽  
pp. 83-91 ◽  
Author(s):  
G. A. Hamill ◽  
J. A. McGarvey ◽  
D. A. B. Hughes
Keyword(s):  
Efflux Velocity

scholarly journals Efflux velocity of oligomers of various viscosity

2020 ◽  
pp. 42-44
Author(s):  
E. M. Razin'kov
Keyword(s):  
Significant Role ◽  
Phenol Formaldehyde ◽  
Housing Construction ◽  
Laminated Beams ◽  
Efflux Velocity

The efflux velocity of oligomers based on carbamide-phenol formaldehyde resins plays a significant role in the manufacture of various types of glued materials, especially laminated beams for housing construction. The efflux velocity of carbamide-phenol formaldehyde oligomer was studied in the context of laminated timber technology.

The characteristics of the turbulence in the mixing region of a round jet

1963 ◽  
Vol 15 (3) ◽  
pp. 337-367 ◽  
Author(s):  
P. O. A. L. Davies ◽  
M. J. Fisher ◽  
M. J. Barratt
Keyword(s):  
Time Scale ◽  
Shear Velocity ◽  
Statistical Characteristics ◽  
Length Scale ◽  
Mean Velocity ◽  
Similarity Relations ◽  
Air Jet ◽  
Local Shear ◽  
Local Intensity ◽  
Efflux Velocity

Measurements in the mixing region of a 1 in. diameter cold air jet are described for Mach numbers ranging from 0.2 to 0.55. The statistical characteristics of the turbulence in the first few diameters of the flow may be expressed in terms of simple kinematic similarity relationships. These are based on the jet diameter and the distance downstream from the jet orifice as length-scales, and the inverse of the local shear as a time-scale. The experiments show that the integral time scale of the turbulence in a frame convected with the maximum energy of the turbulent motion is inversely proportional to the local shear.The most interesting result obtained is that the local intensity of the turbulence is equal to 0.2 times the shear velocity. This velocity is defined as the product of the local integral length-scale of the turbulence with the local shear. The local intensity is defined as the R.M.S. value of the local velocity fluctuations divided by the jet efflux velocity. It was found that the length-scale is proportional to the distance from the jet orifice, while the maximum shear is also related to this distance as well as to the jet efflux velocity. These two similarity relations break down close to the jet orifice and change beyond the first six or so diameters downstream. The convection velocity is not equal to the local mean velocity but varies slowly over the region of maximum shear when it is just over half the jet efflux velocity. The measurements of other observers fit the relationships obtained quite well. From these relationships it is possible to calculate the noise generated by the mixing region of a given jet directly, using expressions derived by Lilley (1958).

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