Unit type ejector with the smallest width and mass. The high velocity primary stream is produced by expanding a high. Most ejectors have a fixed capacity curve as shown in figure 1. The other conditions will then fall within the performance curve of the larger ejector. Basic design, operating information, and operation limitations of air ejectors. Flow through the device is restricted, creating a highpressure area. The loss coefficients k p, k s, k m and k d account for losses in the primary nozzle, secondary flow inlet, mixing chamber and diffuser, respectively.
Download here ejector design calculation pdf download by benjaingry, released 27 october 2016 ejector design calculation pdf download download look at most relevant ejector design. In this study, we write a computer program and simulate the ejector. The term jet ejector describes a device in which a pumping effect is achieved using a motive fluid. First algorithm is used for system ejector design and the second algorithm is used for the performance evaluation. The ejector system should be designed to avoid creating a vacuum in the flare gas line to ensure safe operation. Best a generalized ejector model was successfully developed for gas ejector design and performance analysis. Fluid then explodes through an orifice, creating a lowpressure area that creates. Other types of injector may use other pressurised motive. Ejector modeling and examining of possibility of replacing. Ejector design calculation pdf download anpsortigas. Municipal these systems are designed to serve a given natural drainage area and are part of the public sanitary sewer system.
An ejector is a device used to suck the gas or vapour from the desired vessel or system. To develop mould parameter sofware system with the injection database. Ejector design may be performed at various levels of complexity. A jet ejector requires no mechanical drive and has no moving parts. The reason for the lecture is that if you a trying to pump liquid you dont want to use and ejector velocities get pretty high. For design of an ejector and calculating performance of the ejector, we use some basic mathematical model. Compact type vacuum ejector with a width of 10 mm and a mass of 109 g. In many cases, ejectors are designed in a rather empirical way, and the only elements of the ejector geometry that receive a. Ejector systems ejectors gea engineering for a better world. Ejector design software to do conceptual design and generate ejector sizes. Steam can be used as the motive fluid in either case.
Critical design means that the fluid velocity in the diffuse throat is sonic. This we must find new dimensions of ejector which meets this conditions. In this type of ejector the capacity is a function of the absolute pressure at the suction inlet. In noncritical units the fluid velocity is subsonic. Mathematical model of ejector and experimental verification. Design of sewage pumping stations by john zoeller, pe, ceopresident this article provides guidelines for designing municipal pumping systems. Entropy 2012, 14 602 the calculation of p r3 will then enable the dimensions of the mixing chamber to be determined by calculating its section s 3 as well as the other dimensions of the ejector, which are beyond the scope of this study.
Steam ejector calculation industrial professionals. The major difference between the ejector and the vacuum pump or compressor is it had no moving parts. The motive gas mach no is provided for information. Introduction suction nozzle ejector has been widely used in different cycles for refrigeration purposes, such as recovery of expansion work, utilization of lowgrade energy solar energy, geothermal energy and waste heat. Occasionally an ejector must operate alternately at two or more conditions of load and vacuum. A new approach for determining the main parameters of an ejector is proposed, and a sequence for calculating it is given. Case studysteam jet ejector free download as powerpoint presentation. To design mould parameter calculation sofware system. Pdf design, cfd analysis and performance evaluation of. In the case of liquid jet vacuum ejectors the achievable suction pressure at zero load corresponds more or less to the vapour pressure of the motive liquid. This list of references was sent to me by matija gregorka. Review on ejector efficiencies in various ejector systems.
Free download venturi wet scrubber design calculation books venturi wet scrubber design calculation. Free demo programs for a short time are offered to let you see how the ejector program works they. Convergence percent normally 99% is supplied to confirm. An ejector is similar to an of vacuum pump or compressor. Ejector design calculation, ejector dimensions, generate. Ejector unit consists of ejector plate and ejector back plate. A method of calculation for the ejector design using the present correlations is also presented. Ejector design software ejector sizing calculation. Design requirements for the nozzle, mixing tube and diffuser are similar to those for jet pumps. In addition, r141b is shown to be a good working fluid for an ejector.
Gas ejector design can however ejector performance analysis be determined by rigorous calculation using the figure 1 shows a sketch of gasgas ejector based. The actual performance of the system was compared with that theoretically predicted, and the differences noted were critically examined. Example for design data ejector arrangement for operating conditions ejector jet pump and silencers. Increased intake flow rate using 2stage nozzle structure. The ejector design principles used in the ejector calculations for the program are explained including the ejector energy balance and effects of the ejector flow cones. In the derivation of the formula, the density of the layer of air. Ejector designs can be classified either as critical or noncritical. A steam ejector is of critical design when the suction pressure is lower than approximately 55% of the discharge pressure. Hence it is relatively lowcost and easy to operate and maintenance free equipment. A method for prediction of gasgas ejector performance. Boundaries of the application field of this procedure are revealed.
All jrgjt tables use the 112 inch unit as the standard, and eductors are sized using a sizing factor s. One newton is defined as the force necessary to give a mass of 1 kg an acceleration of 1 ms2. Regimes of ejector operation one crucial consideration in the analysis and design of ejectors is the variety of flow regimes that are possible, depending on operating conditions and the ejector geometry. The calculated section s 3 of the mixing chamber is a function of the ejector operating conditions, in particular of p 1, t. Steam jet ejectors for the process industries robert b. Calculation for the ejector design using the correlations is also developed. Chubb michaud cwsvi eductors, also called injectors, work on the venturi principle. This equipment has many different applications, discussed below. The basic principle of jet pumps consists in the liquid or gas jet being emitted by a nozzle at high speed entraining and accelerating the surrounding liquid, gas or solid matter. Ejector design calculation pdf download unger i hedmark l. So for example, the suction pressure cannot be below 23 mbar 17,5 mm hg for a jet ejector with water as a. In order to design for maximum ejector efficiency one. In this paper, the steam jet ejector was designed and then the cfd analysis was carried out for the geometry and the inlet condition data verified by the performance evaluation of the jet ejector.
Material of construction is corrosionresistant and corrosiontested duplexstainless steel, which is coated with sprayed aluminum. Basiclly, this steam ejector is use as a medium to create the vacuum area in order to suck the pigment and channel it into micronizerfor milling. How to calculate the flowrate of motive fluid in an ejector free download as pdf file. The application below will give the required inlet pressure and water flow needed with each size eductor at various discharge pressures. The application determines the design of the flow section. Results obtained from an analysis of the most widespread and commonly used procedure for calculating gas ejectors equipped with a cylindrical mixing chamber are presented. A general simulation of an air ejector diffuser system.
Lowgrade thermal energy can be used to drive this system. This basic principle applies to every jet ejector in different models and ranges of application. In this instance the ejector must be designed for the most difficult conditions or the conditions that call for the largest ejector. Previous 1d analytical models can be derived from this new. Empirical correlation for ejector design sciencedirect. Make sure that flow and pressure are available under flowing conditions. An ejector is intended to move high gascut fluids and has a convergent section for an entry to the straight throat which is again followed by a divergent section. Onedimensional model of an optimal ejector and parametric. A procedure for calculating gas ejectors springerlink. So, do you have a calculation in order to calculate how. When first developed, its operation was intriguing because it seemed paradoxical, almost like perpetual motion, but it was later explained using thermodynamics. Feasibility study of replacing steam ejector with liquid. The ejectorbody is designed for 7 barg the motive side for 2 barg.
Therefore ejector curves at fixed ejector geometry are calculated at the design discharge pressure and an increased discharge pressure see 3. In a steamjet ejector, the suction chamber is connected to the vessel or pipeline that is to be evacuated under vacuum. Liquid jet vacuum ejectors can extract gases and vapours and compress them. The lack of a systematic and rational design method instigated the present investigation, of which the preliminary results were. Review of ejector design parameters and geometry for.
A steam injector is typically used to deliver cold water to a boiler against its own pressure, using its own live or exhaust steam, replacing any mechanical pump. Increasing the steam pressure above the design pressure will not increase the capacity of the ejector. A general simulation of an air ejector diffuser system derick thomas daniel university of tennessee knoxville, derick. How to calculate the ejection force walshs plastic.
Since an ejector has no valves, rotors, pistons or other moving parts, it is a relatively lowcost component is easy to operate and requires relatively little maintenance. Liquidgas ejectors these ejectors utilize liquid as the primary fluid. Steam ejector calculations free download as excel spreadsheet. The acceleration due to gravity is normally taken as 9. These are more indicative of the response of a specific ejector to changes in inputs.
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