Experimental and numerical analysis of a variable area. With the advent of supersonic turbojet aircraft, exhaust nozzles are. Experimental study on a multievaporator refrigeration. When afterburning engines are equipped with a cd nozzle the throat area is variable. For this test it was required that the nozzle be held at a well defined minimum area under all loads, but also it must be able to hold a progra mmed area up to 20% larger as. Predicted performance of a thrustenhanced sr71 aircraft with an. Performance characteristics of a variablearea vane nozzle for.
When defining certain types of jet ejectors, the standard terms for motive flu. Ar decides the velocity and pressure of the driving flow at the nozzle exit. Experimental investigation on motive nozzle throat diameter. The input and output files and comparisons of the velocity and total temperature profiles can be found on the unstructured ejector nozzle page.
In this paper, computational fluid dynamics cfd is employed to investigate the effects of the area ratio of the ejector constantarea mixing section to the nozzle throat, the length of the. As a specific result, they found that for a fixed geometry, the ejector is very. Study on the performance of a variable geometry ejector. Pdf the benefits of variable area fan nozzles on turbofan. Variable area nozzles are used for adjusting the exit area for different. Based on the ejector model, there is an optimal nozzle position of 6 mm for a given operating conditions and fixed geometries of this designed ejector, which contributes the highest entrainment. A theoretical analysis of a variable area ejector is presented. Two geometrical factors, the area ratio and the nozzle exit position, can be actively controlled. The experiments indicated that energy saved was raised to 112% by the. This result implies that each of the cavities could pump the same.
In this work, three geometrical factors the area ratio between the nozzle and constant area section, nozzle exit position and constant area section length were considered. The variable area mixing ejector has been developed based on a onedimensional constant rate momentum change gas dynamic theory. The geometry of a constant pressure design includes a variable. The throat area is usually two to four times larger than the nozzle area. Exhaust nozzles the three exhaust nozzles selected for this program were a cylindrical ejector, an. The gains obtained by ejectors and by corrugated nozzles are to a certain extent additive in that a combination of a corrugated or multiple nozzle and an ejector reduce the aerodynamic noise of a jet still further.
Predicted performance of a thrustenhanced sr71 aircraft. A motive nozzle needle allows precise adaption on varying. Ejector nozzle, ejector nozzle suppliers and manufacturers. The major drawback of such a system is associated with its relatively low coefficient of performance cop under variable operating conditions. An ejector performance curve gives the expected suction pressure as a function of. Request pdf analysis on performance characteristics of ejector with variable area ratio for multievaporator refrigeration system based on experimental data this paper presents a study on.
The ejectors tested had a constant exit area and variable primary area to provide nozzle area ratios from 1. Experimental results with a variable geometry ejector using. Circuit diagram exe v p vacuum ejector inline type zu series rohs type high vacuum type large flow type model zu05s zu07s zu05l zu07l nozzle diameter mm 0. This study presents a comprehensive numerical, experimental study and analysis on the effect of nozzle exit position nxp on variable area mixing ejector.
A variable ejector for a jet engine having a variable area nozzle, said engine being enclosedby a casing, said ejector comprising a sleeve surrounding the casing of said engine and disposed adjacent the rearward portion thereof. The ejector nozzle flowfield was solved on an unstructured grid using the unstructured grid solver in windus 3. Ejector refrigeration is a promising technology for the integration into solar driven cooling systems because of its relative simplicity and low initial cost. The application potential of ejectors in other areas of interest remains. Readdressing working fluid selection with a view to designing. In an increasing number of applications it is necessary to apply controls. In the divergent parts, the friction loss may be taken as 0. Jot ames research center national aeronautics and space administration washington, d. The convergent parts of the nozzle are sharp and frictionless. Jul 01, 2014 read analysis on performance characteristics of ejector with variable area ratio for multievaporator refrigeration system based on experimental data, applied thermal engineering on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Selecting an eductor the venturi is a teeshaped device that passes fluid through a restricting nozzle see figure 9, increasing its flow velocity and. Li and yan 8 carried out an investigation of the variable area ratio ejector on a multi evaporator refrigeration system. Comparison of predicted and experimental wall temperatures. An efficient nozzle provides high kinetic energy at the nozzle outlet for high pressure recovery in the ejector. Cfd study of a variable area ratio ejector using r600a and. The control of the area ratio is achieved by a movable spindle installed in the primary nozzle. Therefore, they react to control impulses in a manner peculiar to their. The areas of both the propelling nozzle and turbine nozzle set the mass flow through the engine and the maximum pressure. Development and performance of an advanced ejector cooling. Ejectors are essentially a fixed capacity device since the diffuser area is constant. A that the entry speed can be neglected, only modifies the flow inside the nozzle, but not the exit conditions. Research and technology development activities were carried out at the rollsroyce university technology center for high mach propulsion, purdue university. This figure represents the main parts of the ejector such as a nozzle, three types of constantarea sections including discharge and an adjustable spindle of the primary inlet that ranges from 0 fully closed to.
Ejector modeling and examining of possibility of replacing. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed. If the amount of leakage is known based on the effective sectional area of the side with the leakage, the vacuum pressure can be estimated in accordance with the ejectors flowrate characteristics. The short ejector fiap added to the primary nozzle offers an easy lightweight solution tothe pumping problem associated with the tertiary inlet nozzle. The leaves translate on a rollertrackcage arrangement, causing a change in the nozzle convergence angle fig. Why are adjustable area jet engine nozzles mostly limited to. About 5% of these are water treatment, 4% are pumps, and 4% are moulds.
A propelling nozzle is a nozzle that converts the internal energy of a working gas into. A variable area nozzle van on the bypass stream of a turbofan engine may prove to be necessary for a sufficient surge margin on an ultrahigh bypass ratio fan. Readdressing working fluid selection with a view to designing a variable. For this operation condition, the diameter of the motive nozzle throat for the designed ejector was 2. Ejector refers to the pumping action of the very hot, high speed, engine. The objective was to validate the unstructured solver for the ejector nozzle flow. Pdf effect of nozzle exit position nxp on variable area mixing. Experimental observation for multi nozzle liquid jet ejector for chlorineaqueous caustic soda system at laboratory scale k. Experimental observation for multi nozzle liquid jet ejector. By being supported on and riding with the primary nozzle, when the nozzle is variable, the ejector flap is also variable. Theoretical and experimental investigations of different. Steam expands in a set of nozzle from 10 bar, 300 0c to 1 bar. All stainless steel vacuum ejector smc corporation.
Experimental study on a multievaporator refrigeration system. Primary nozzle the variable area primary exhaust nozzle is made up of overlapping leaves that provide a nearly circular throat. Variable flow ejectors are based on proven gea jet pump. Preliminary design and computational analysis of an ejector. A variable area nozzle helps to adjust the exit pressure of the combustion gases to ambient pressure. The ejector depicted in figure 2 is comprised of the convergingdiverging cd nozzle at the primary inlet, the suction chamber housing the secondary inlet, the constant area mixing chamber and the recovery diffuser.
Case file copy analysis and testing of twodimensional slot nozzle ejectors with variable area mixing sections by gerald b. Gea jet systems are reliable and require low maintenance. The model which is developed based on integration equations momentum as well as energy for different parts of ejector, using special. Install the new oring on the accelerator pump ejector nozzle picture 7 and the new bowl gasket, included in the kit, on the carb body picture 8, and reinstall the bowl on the carburetor using the screws removed in step 1. In order to overcome this problem, an advanced ejector was developed that changes its. While both these areas are fixed in many engines i. Analysis on performance characteristics of ejector with. Understanding ejector systems necessary to troubleshoot. Experimental results with the first laboratory scale variable geometry ejector vge using isobutane r600a are presented. Pdf a number of numerical and experimental studies have been devoted to the modeling of highperformance steadyflow ejectors in different. Agrawal assistant professor, department of chemical engineering faculty of technology and engineering, the m.
This work tries to analyse the performance of a steam ejector working in conjunction with a refrigeration cycle. Reinstall the carburetor on the engine, if removed, and attach the. Over expanded and under expanded nozzles, ejector and variable area nozzles, interaction of nozzle flow with adjacent surfaces, thrust reversal. The efficiency of the ejector cycle is very sensitive to the ejector efficiency. The present experimental study is performed on the basis of an ejector with variable area ratios. Theoretical investigation of variable area ejectors carleton. Several researches on convergingdiverging nozzles for the ejector refrigeration cycle were done. Optimization of a highefficiency jet ejector by computational fluid dynamics software. Effects of the nozzle configuration on solarpowered.
Determination of efficiency of converging diverging nozzles. Based on the designed ejector, effects of motive nozzle throat diameter on performance were studied under conditions of 5 c evaporator temperature and condenser temperature of 40 c. Tests were conducted at nozzle pressure ratios ranging from. Sufficient mixing requires a long ejector the ejector length should be approximately eight times its diameter. Propelling nozzles may have a fixed geometry, or they may have variable. Hill prepared by dynatech rd company cambridge, mass. Readdressing working fluid selection with a view to designing a variable geometry ejector.
Internal performance of several types of jetexit configurations for. Jan 06, 2011 the ejector nozzle flowfield was solved on an unstructured grid using the unstructured grid solver in windus 3. When they leave the turbine, the combustion gases have still some remaining pressure which is converted into speed by a convergent contour of the nozzle. The definitions of overall ejector efficiency and ejector component efficiencies in literature are. This is a pdf file of an unedited manuscript that has been accepted for publication. Variable area jet nozzle for noise reduction using shape. Effect of nozzle exit position nxp on variable area. That suction draws chemicals or slurries into the device, mixes it with the feedwater and pushes it downstream.
If the steam floe rate is 1 kgs and the initial velocity of steam is negligible, find the minimum area of the nozzle. Controlling ejector performance pumps operating on the ejector principle are in use on many processes. Review on ejector efficiencies in various ejector systems. Expired lifetime application number us102677a inventor frank v purse. A shock wave occurs in the diffuser throat when the compression ratio of an ejector is 2.
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