Ejector and variable area nozzle pdf merge

Comparison of predicted and experimental wall temperatures. Gea jet systems are reliable and require low maintenance. The cooling of the exhaust nozzle of a fan jet engine powering aircraft is enhanced by providing an extension cooling concept that includes an extension piece extending axially downstream of the nozzles variable throat that utilizes fan air to cool the forward portion of the divergent nozzle surfaces adjacent to the gas path of the engine and ram air to cool the surfaces downstream of the ejector. The ejector mode of rocketbased combined cycles is a concept that has the. Ejector efficiency is found to be highest at low compression ratios and at low driving pressure ratios. Ejector nozzle, ejector nozzle suppliers and manufacturers at. Research and technology development activities were carried out at the rollsroyce university technology center for high mach propulsion, purdue university. The flow properties computed based on the theory and simulation along the variable area mixing ejector are validated. By being supported on and riding with the primary nozzle, when the nozzle is variable, the ejector flap is also variable.

Ejector performance with two working fluids r152a and r600a is analysed. Us6301877b1 ejector extension cooling for exhaust nozzle. A that the entry speed can be neglected, only modifies the flow inside the nozzle, but not the exit conditions. A variable area nozzle helps to adjust the exit pressure of the combustion gases to ambient pressure.

The geometry of a constant pressure design includes a variable. 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. As a specific result, they found that for a fixed geometry, the ejector is very. Figure 3a is a schematic view in detail of a variable nozzle and a variable ejector. Analysis on performance characteristics of ejector with. The influence of the area ratio, using a spindle and the nozzle exit position tested. R600a is a good choice for working fluid in the range of tested conditions. Review of ejector design parameters and geometry for refrigeration and air conditioning application. A wide variety of ejector nozzle options are available to you, such as free samples, paid samples. The difference is with respect to their function and not with respect with their. A few literature researchers have studied the effect of nozzle diameter on jet ejector performance. We will find the new ejector which has greater mass flow rate in the suction branch mass flow of air than the original ejector for pressure 90100 kpa.

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. As nouns the difference between ejector and eductor is that ejector is one who, or that which, ejects or dispossesses while eductor is one who, or that which, brings forth, elicits, or extracts. Forest service model 62 engine to the ejector at a water source figure 2. The nozzle 36 includes a plurality of chute ejectors 38 placed equal distances about the circumference of a nozzle outer structure 46. The exchange inlet is compared to a conical nozzle within a rbcc.

Highlights a numerical analysis of two ejectors with variable geometry is presented using cfd. Experimental study on a multievaporator refrigeration. The internal compressible flow through an ejector has many complex gas dynamic features, like. Hello,could anyone please educate me the differences between eductor and ejector.

Figure 3 is a schematic elevational view of a typical aviation turbo jet power plant having an afterburner, a variable nozzle and a variable ejector constructed in accordance with the invention. Theoretical investigation of variable area ejectors. Optimal spindle positions are presented depending on operating conditions. A method is proposed for calculating the twodimensional nonviscous flows in ejector nozzles of arbitrary shape, for two operating cycles. Primary nozzle the variable area primary exhaust nozzle is made up of overlapping leaves that provide a nearly circular throat area. A test program was run to provide twodimensional ejector test data for verification of the computer analysis. The variable area mixing ejector has been developed based on a. This study presents a comprehensive numerical, experimental study and analysis on the effect of nozzle exit position nxp on variable area mixing ejector. By inserting a movable needle into the nozzle throat as shown in fig. The 1d gas dynamic crmc theory for variable area mixing section ejector design is utilized for the study of the effect of nxps. Cop increased by up to 24% for the variable geometry ejector when compared to a fixed geometry ejector, operating off design conditions.

A numerical analysis of two ejectors with variable geometry is presented using cfd. A primary converging nozzle with a discharge geometry of 0. A tertiary inlet ejector nozzle for a jet engine having spaced outer and inner casings forming a cooling flow passage around the engine, l l. Development and performance of an advanced ejector cooling. Study of the configuration and performance of airair ejectors.

The research nozzle gross thrust minus drag was determined by subtracting the tare force from the compensated loadcell reading. Theoretical investigation of variable area ejectors by mikhail koupriyanov a thesis submitted to the faculty of graduate studies and research in partial ful. Variable flow ejectors are based on proven gea jet pump. The definitions of overall ejector efficiency and ejector component efficiencies in literature are. Ejectors are essentially a fixed capacity device since the diffuser area is constant. Experimental and numerical analysis of a variable area ratio steam. Controlling ejector performance pumps operating on the ejector principle are in use on many processes. Considerable leakage from the suction surface if a workpiece is made of porous material or if there is air leakage from the area between the pad and the workpiece, use a nozzle with a.

The efficiency of the ejector cycle is very sensitive to the ejector efficiency. An exterior fairing is spaced radially outwardly of the divergent section. Why are adjustable area jet engine nozzles mostly limited to. A thesis submitted to the faculty of graduate studies and research in partial ful. Mathematical model of ejector and experimental verification. Sufficient mixing requires a long ejector the ejector length should be approximately eight times its diameter. 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. Experimental and numerical analysis of a variable area. However, at lower compression ratios, the optimal area of the mixing chamber becomes large relative to the motive nozzle throat area.

The optimum length and diameter of the throat section, the nozzle position, and the radius of the inlet curvature before a convergence section in a constant area jet ejector design are investigated for. Although engine fuel flow and airflow were measured during the test, the primary gas pressure, primary temperature and primary nozzle area were not measured but were assumed to be equal to the published values of. If the aircraft is to fly at supersonic speeds, the afterburner nozzle may be followed by a separate divergent nozzle in an ejector nozzle configuration, as below. A general simulation of an air ejector diffuser system derick thomas daniel university of tennessee knoxville, derick. Ejector nozzle, ejector nozzle suppliers and manufacturers. The areas of both the propelling nozzle and turbine nozzle set the mass flow through the engine and the maximum pressure. The major drawback of such a system is associated with its relatively low coefficient of performance cop under variable operating conditions. A general simulation of an air ejector diffuser system derick thomas daniel university of tennessee. Army research offica grant number dahc 0474g0112 and department of mechanical and industrial engineering university of illinois at urbanachampaign urbana, illinois 61801. The objective was to validate the unstructured solver for the ejector nozzle flow. An ejector as claimed in claim 1 including an elongated fixed plug disposed in said duct in axial alignment with said elongated movable plug and defining with said duct a diffuser nozzle. The ejector nozzle flowfield was solved on an unstructured grid using the unstructured grid solver in windus 3. In an increasing number of applications it is necessary to apply controls. An efficient nozzle provides high kinetic energy at the nozzle outlet for high pressure recovery in the ejector.

Gathering all the terms and combining back into one equation yields the fans equa tions for. 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. An integration of the turbojet and singlethroat ramjet. This model most realistically predicts the operational characteristics of ejector systems. Variablearea ejector wall pressure distributions w 0516, m pl 2. Pdf effect of multiple nozzles on air ejector performance. An ejector as claimed in claim 1 wherein said movable plug concomitantly changes the area of the primary nozzle and the longitudinal crosssectional area. Ejector refrigeration is a promising technology for the integration into solar driven cooling systems because of its relative simplicity and low initial cost. Effect of nozzle exit position nxp on variable area. Table 1 ejector versus suctiondrafting performance characteristics. Determination of efficiency of converging diverging.

Er increases with increasing ejector area ratio ar. Hence the eductors can be used to transfer a considerable volume of fluid from low pressure to high pressure with high compression ratio than ejectors. In order to overcome this problem, an advanced ejector was developed that changes its. The primary nozzle, which is illustrated in detail, has an inlet diameter d 1 of 15 mm, a throat diameter d t of 4 mm and an exit diameter d 2 of 6 mm. Optimization of a highefficiency jet ejector by computational fluid dynamics software. The input and output files and comparisons of the velocity and total temperature profiles can be found on the unstructured ejector nozzle page. Ejectorbased refrigeration systems combine the rankine cycle and. An ejector cooling air flowpath leads from an ejector cooling air inlet in an aft portion of the fairing to a cooling air ejector in the nozzle. It should be noted that the ability of spindle to adjust the primary flow rate has already been proved by the analysis of varga s. About 5% of these are water treatment, 4% are pumps, and 4% are moulds.

Pdf a number of numerical and experimental studies have been devoted to the modeling of highperformance steadyflow ejectors in different. Selecting an eductor the venturi is a teeshaped device that passes fluid through a restricting nozzle see figure 9, increasing its flow velocity and. The ejectors tested had a constant exit area and variable primary area to provide nozzle area ratios from 1. The variable area iris nozzle consists of a series of moving, overlapping petals with a nearly circular nozzle crosssection and is convergent to control the operation of the engine. It does not have an intercondenser between the first and second stages. This we must find new dimensions of ejector which meets this conditions. Tests were conducted at nozzle pressure ratios ranging from. The relationship and correspondence between variable area and constant area mixing tube ejectors should be established by both experiment and analysis. A gas turbine engine exhaust nozzle includes a divergent section located aft of a convergent section and a throat therebetween. A supersonic ejector is used to pump a secondary gas using a supersonic primary gas flow by augmentation of momentum and energy in a variable area duct.

Rocket nozzle design with ejector effect potential carleton. The effect of nozzle exit positions nxps has been studied for variable area mixing ejector. Six different area ratios of ejector using air as working fluid in this study were proposed and tested experimentally. Variable area jet nozzle for noise reduction using shape. Variable area nozzles are used for adjusting the exit area for different operating conditions of the engine. The maximum allowable engine size to avoid reverse flow in the ejector increases slightly with the primary nozzle area ratio. This modelling technique could combine the simplicity of the lumped. Cfd study of a variable area ratio ejector using r600a and. 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. An investigation of the constant area, supersonicsupersonic ejector. Preliminary design and computational analysis of an ejector.

Oct 28, 1997 at the downstream end of the intermediate casing 68, the first bypass duct inlet 62 and second bypass duct inlet 66 merge into a common bypass duct, shown generally at 74. The principle of operation of ejectors is based on the venturi effect of a convergingdiverging nozzle to convert the pressure energy of a motive fluid primary flow to kinetic energy to entrain a suction fluid secondary flow, and then recompress the mixed fluids by converting kinetic energy back into pressure energy figure 1. The application potential of ejectors in other areas of interest remains. A supersonic ejector utilizes the energy and momentum of a primary motive jet to entrain and compress a secondary coflow. Review on ejector efficiencies in various ejector systems. Maximum turbojet engine size was desired because of takeoff and transonic thrust requirements. Two sets of ejectors a and c are studied and examined depend on the kind of nozzle. These conditions were chosen because they are readily available. Ejectors have a number of primary variables of interest which are the. For this configuration, the after burner was modified by removing the variable area primary nozzle and substituting a plug mounted within a fixed 17 halfangle conical nozzle creating an annular exit area of. Modeling an air ejector diffuser system for a hypersonic propulsion test facility includes. Abstractin this study, ejector mathematical models have been presented based on thermodynamic relations governing it and in order to have an ejector computer simulation. The ratio of mass flow entrained through the ejector nozzle to that passing through the primary jet nozzle, m. Determination of efficiency of converging diverging nozzles.

Performance comparison of ejector expansion refrigeration. 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. Theoretical investigation of variable area ejectors carleton. Numerical investigation of a novel rbcc ejector configuration. Variable area ejector results in better performance than fixed geometry design. The variable area mixing ejector has been developed based on a onedimensional constant rate momentum change gas dynamic theory. Significant variation of decompression profiles occur in the. Request pdf experimental and numerical analysis of a variable area. Review of ejector design parameters and geometry for. The performance of convergingdiverging nozzles with varying length of diverging sections for the ejector refrigeration. Over expanded and under expanded nozzles, ejector and variable area.

Variable flow ejectors are based on proven gea jet pump technology and often used for heat recovery. It is a pure aerodynamic device that has no moving parts and the flow is brought about by just gas dynamics of the two flows confined within a variable area duct. The pp corresponding to the maximum er of ejectors with a different nozzle exit position nxp is 3. A users guide for the differential reduced ejector. Four rectangular convergingdiverging nozzles with divergence angles of 0. Glover research was performed to optimize highefficiency jet ejector geometry holtzapple, 2001 by varying nozzle. Potential technical implementations to adjust the area ratio between the constant area section and primary nozzle throat section can be. Comparison of novel variable area convergentdivergent. Ejector efficiency, entrainment ratio, onedimensional model, perfect expansion. Ejector performance analysis under overall operating.

Furthermore, the constantarea and variablearea ejectors were compared in terms of cfd and experiments at the same operating conditions. The ejector nozzle continues as a circular duct of crosssectional area a and has sufficient length to ensure that mixing between primary and ejector flows is. Calculation of the flow in ejector nozzles springerlink. What is the difference between the eductor and ejectors. All stainless steel vacuum ejector smc corporation. Both geometrical factors influenced cooling cycle performance, optimal area ratio depends on operating conditions. The freejet nozzle is a fixed area nozzle that is designed for a specific number flow, and for this mach. Variablearea, slottednozzle ejector wall pressure distributions aa. The model which is developed based on integration equations momentum as well as energy for different parts of ejector, using special. The variable geometry ejector has been used by researchers with.

Applying a variable geometry ejector in a solar ejector. An aircraft axisymmetric exhaust nozzle 36 is provided for reducing noise in an intermediate bypass ratio turbofan engine. Analysis and testing of twodimensional slot nozzle. Pdf effect of the nozzle exit position on the efficiency. Therefore, they react to control impulses in a manner peculiar to their. Pdf the benefits of variable area fan nozzles on turbofan. In the second case, the possibility is allowed for the appearance of a direct compression shock in the supersonic part of the. Several researches on convergingdiverging nozzles for the ejector refrigeration cycle were done. Onedimensional model of an optimal ejector and parametric. That suction draws chemicals or slurries into the device, mixes it with the feedwater and pushes it downstream. The variable area ratios of ejectors a 2 a t were used with a range from 10.

A general simulation of an air ejector diffuser system. Analysis of the system the ejector expansion vapour compression refrigeration cycle has been modeled based on following conservation laws and equations. A motive nozzle needle allows precise adaption on varying. These two types of ejectors were tested in a steam jet refrigeration system. Ejector modeling and examining of possibility of replacing. Supersonic ejectordiffuser theory and experiments dtic. Effect of the nozzle exit position on the efficiency of ejector cooling system using r4a. Preliminary design and computational analysis of an.

Jan 06, 2011 the ejector nozzle flowfield was solved on an unstructured grid using the unstructured grid solver in windus 3. The features of the concept were clearly described in both cases. Theoretical and experimental investigations of different. The results show that the variable area ejector increases the pressure lift ratio up to 40% by eliminating a shock wave from the ejector.

Rocket nozzle design with ejector effect potential by david j. At the primary nozzle exit station the ejector nozzle velocity is u and the pressure is constant and equal to p j. Conveniently, to control the gap, the ejector flap may be larger than the primary flap and the downstream end may be curved or turned at 46 to be substantially parallel with the longitudinal centerline of the engine and reduce any discontinuities in the supersonic flow. Dsl dividing streamline e propelling nozzle exit i ejector inlet m mixed flow ejector exit r rocket ref. Analysis and testing of twodimensional slot nozzle ejectors with variable area mixing sections. Combining figure 6 with the definition of the er, it can be inferred that. Compressor splitter for use with a forward variable area.

The present experimental study is performed on the basis of an ejector with variable area ratios. Effects of the nozzle configuration on solarpowered. Experimental investigations on supersonic ejectors core. While both these areas are fixed in many engines i. Pdf effect of nozzle exit position nxp on variable area mixing.