Flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure ratio,supersaturated flow. Triad is an industry leader in the design, manufacture and testing of ptc6 flow nozzles for final feed water flow and condensate measurement applications. Mar 07, 2015 vanita thakkar bit 52 supersaturated flow when steam flows expands through a nozzle, it would be normally expected that the discharge of steam through the nozzle would be slightly less than the theoretical value. The theory of the nozzles be can use for calaculation of a flow through a group of turbine stages at change of state of the gas in front of or behind this group of the stages. Steam flow measurement measuring steam energy evaluating important design and installation considerations overview of current technologies. Numerical study on condensation process of steam flow in nozzles. Triad manufactures flow nozzles for power generation, chemical plants and refineries, pipeline and off shore gas processing. What are the various types of nozzles and their functions. Consider a unit mass flow of steam through a nozzle. Mass flows of gases and vapours through nozzles according to the law of continuity m a w. Compressible flow part 3 of 4 nozzles and diffusers duration. Nozzles are widely used in technology in, for example, steam and gas turbines, rocket engines, airbreathing jet engines, gas lasers, equipment used in magnetogas dynamics, wind tunnels, test benches used in gas dynamics, jet devices, and flowmeters. Flow of steam through pipes and orifices gutenberg. Density of flowing medium p 1 pressure before the nozzle.
This higher efficiency means greater flow capacity when compared to most other differential meters of the same size. Flow of liquids through nozzles find more information in the tp410 2009 edition. From heating liquid continuous from heating liquid batch from heating air. This article provides calculation methods for correlating design, flow rate and pressure loss as a fluid passes through a nozzle or orifice. Sizing steam pipes steam is a compressible gas where the capacity of a pipe line depends on the size of the pipe and the steam pressure. Isentropic expansion expansion in a steam turbine steam from the boiler. Write short note on supersaturated flow on steam nozzles. When steam is expanded isentropically from 12,it is expected that phase change occurs at point x. Isentropic nozzle flow describes the movement of a gas or fluid through a narrowing opening without an increase or decrease in entropy. How to calculate the steam flow through each nozzle. Pdf discharge coefficients for compressible flow through.
Numerical study on condensation process of steam flow in. Apr 03, 20 flow of steam through nozzles universalppts. Unit iii unit iii steam nozzles and turbines flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure ratio, supersaturated flow. Steam nozzles and turbines flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure ratio, supersaturated flow. The effect of this friction, in resisting the flow and in drying the steam, must be taken into account in the design of steam nozzles, as it makes an appreciable difference in the results. As a matter fact, when the steam flows through a nozzle, some loss in its enthalpy or total heat.
Supersaturated flow or metastable flow through nozzles. Vtunptelnmeict project progress report the project on. Modeling a spray nozzle engineered software knowledge base. For exact geometry and specifications for nozzles, see iso 1991 or asme 1971. Unit 4 flow through nozzles velocity and heat drop, mass discharge through a nozzle, critical pressure ratio and its significance, effect of friction, nozzle efficiency, supersaturated flow, design pressure ratio. Supersaturated flow is also called as metastable flow. Whenever a gas is forced through a tube, the gaseous molecules are deflected by the tubes walls. Critical flow nozzles are also called sonic chokes. Quasi one dimensional implies that we still have variations of flow quantities in one direction only but we allow the cross section area of stream tubes to vary along the same direction as well. How to determine the steam flow in the nozzles of the stage. This paper describes the results of an investigation into the use of critical flow venturi nozzle flowmeters with wet saturated steam.
Unit 4 flow through nozzles velocity and heat drop, mass discharge through a nozzle, critical pressure ratio and its significance. These nozzles have a variety of application including feed water, steam, natural gas, etc. Dec 08, 2018 at point 1 the steam is in superheated region and at point 2 steam is in wet region. But, experiments on flow of wet steam show that discharge is slightly greater than that calculated by the formulae. Nozzle article about nozzle by the free dictionary. For each type, a constriction in the flow path causes a pressure drop across the meter. Discharge coefficients for compressible flow through smalldiameter orifices and convergent nozzles. Steam ejector is an important component in engineering applications, which require high. Sep 06, 2015 maximum mass flow through a convergent nozzle is obtained when the pressure ratio across the nozzle is the critical pressure ratio.
Vanita thakkar bit 52 supersaturated flow when steam flows expands through a nozzle, it would be normally expected that the discharge of steam through the nozzle would be slightly less than the theoretical value. In this situation the flow rates and dp are comparable to the two models above, but this is highly dependent on the hazenwilliams c factor, the pipe sizes, and the use of water at 60f. The following are the effects of friction on the flow through a steam nozzle. In the step of admission of steam turbines reation there are several nozzles that distribute the steam to the blades. The steam possessesa very high velocity at the end of the expansion, and the enthalpy decreases as expansion occurs. The flow of supersaturated steam, through the nozzle is called supersaturated flow or. In the case of a simple concentric restriction orifice the fluid is accelerated as it passes. Because pressure cannot travel upstream through the supersonic flow, the exit pressure can be. Hello i welcome you all in this course on steam and gas power systems today we will discuss efficiency and critical pressure for a flow inside the nozzle and. At the exit, p2 15 bar, and the velocity is 665 ms. Various formulae for the flow of steam through pipes have been advanced, all having their basis upon bernoullis theorem of the flow of water through circular pipes with the proper modifications made for the variation in constants between steam and water. Also for a convergent divergent nozzle, with sonic velocity at the throat, the crosssectional area of the throat fixes the mass flow through the nozzle for fixed inlet conditions.
The realgas flow coefficient has been calculated using the equations of state for steam, which show the steam behaviour to be far from ideal along the saturation line. For reference to older versions of pipeflo see attachments below. Steam flow orifices steam flow through orifices for steam pressures ranging 2 300 psi. Impulse and reaction principles, compounding, velocity diagrams for simple and multistage turbines, speed regulationsgovernors and nozzle governors. Full text of experimental researches on the flow of steam.
Full text of the theory of the flow of steam through nozzles. Coefficient of loss the aforementioned equation is valid for. Differential pressure is the pressure difference p 1 p 2 shown in the above diagrams. Mechanical power engineering department faculty of engineering. Chapter 5 adds to the theory presented in chapter 3 by extending the equations from ondimensional flow to quasi onedimensional flows. How to determine the steam flow in the nozzles of the. Nozzle is a duct of varying crosssectional area in which the velocity increases with the corresponding drop in pressure. The use of critical flow venturi nozzles with saturated wet steam. The pressure profiles through a convergentdivergent nozzle were measured using an inertgasinjection technique. Calculation of flow through nozzles and orifices neutrium. The critical weightflow rates for potassium vapor were determined by use of a volumetric measure ment te. Feb 12, 2017 lecture series on steam and gas power systems by prof. Another complication in the design of steam through a nozzle is due to a phenomenon. Unit iii steam nozzles and turbines flow of steam through.
The discharge coefficients are the same for both types of venturi nozzles. Friction exists between the steam and the sides of the nozzle. Experimentally the outlet velocity of air from the nozzle system is determined and discussed in chapter 4. The steam flows through the nozzle with negligible heat transfer and no significant change in potential energy. Let v1 velocity of steam at the entrance of nozzle in ms. Pipe flow measurement flow nozzles iso 51673, bs 10421.
The smooth inlet of the flow nozzle results in a higher coefficient of discharge than most other differential meters. Experimental nozzle expansion and flow characteristics of. Lecture series on steam and gas power systems by prof. E 3 units with a vena contracta diameter closer to that of the bore have a smaller deviation and hence a larger coefficient. Nozzles and diffusers efficiency and critical pressure nptel. When the supersaturated steam gets expanded in the nozzle the condensation occurs in the nozzle. In general, devices that control and guide the fluid in its path into, through and out of the element have coefficients nearer to unity e. When an incompressible fluid passes through a converging nozzle with particular velocity then the exit velocity depends only on inlet and exit areas. But practically because of very small length of nozzle, great. Supersonic flow in cdnozzles presents a rich behaviour, with shock. Online calculator to quickly determine steam flow rate through a valve. What are the effects of friction on the flow through a steam nozzle. Nozzles are typically used in 5 to 50 cm diameter pipes.
These processes must be taken into account when calculating the gas flow in the nozzle. Function of nozzle applications and types flow through. Air flow was primarily studied, but data for carbon dioxide, argon, helium, and. Initially when back pressure pb is equal to p1 there shall be no flow through the nozzle but as back pressure pb is reduced the mass flow through nozzle increases. The flow of steam through nozzles may be takenas adiabatic expansion. Differential pressure flow elements dp primary elements.
The maximum gas flow through a nozzle is determined by critical pressure. Modeling a sprinkler system or a system with nozzles old. In addition, the pressure of the gas at the exit of the expansion portion of the exhaust of a nozzle must not be too low. Flow through group of nozzles, flow through group of turbine stages. Nozzles and orifices are often used to deliberately reduce pressure, restrict flow or to measure flow rate. The pressure drop can be measured and correlated with flow rate. An experimental investigation was undertaken to determine the nozzle expansion and flow characteristics of potassium vapor. Pipe flow measurement is often done with a differential pressure flow meter like the orifice, flow nozzle, and ventruri meter.
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