Steam nozzle exit velocity.
0 = 2gH is sometimes called the “spouting velocity”.
Steam nozzle exit velocity Superheated steam enters a convergent nozzle at 150 bar, 500 C and flows isentropically to the exit at sonic velocity. If the cross-section of the nozzle decreases continuously from the entrance to exit, then it is called a convergent nozzle, as shown in Fig. Problem 2 looks at dry saturated steam at 15 bar Steam flows through a nozzle at a mass flow rate of \(\dot m = 0. exit velocity of nozzle Vw1= Tangential component of entering steam , also known as velocity of whirl at entrance Vr1= relative velocity of steam wrt tip of blade at inlet , it is the vectorial difference between Vb and V1 The Exit Velocity of The Nozzle By ap plying steady flow energy equation to the nozzle as a st r eam of fluid at a pressure (P 1 ), enthalpy (h 1 ) and with a low veloc ity (C 1 or V 1 ): Question: Steam enters a nozzle at 800 kPa and 280°C at negligible velocity and discharges at a pressure of 525 kPa. Historically, the theory of the flow of steam through nozzles was developed first in the late 1800 and early 1900 s. 400°C 800 kPa 10 ms Steam 375°C 400 kPa 0 The velocity of the steam at the nozzle exit is m/s. ; The chief use of nozzle is to produce a jet of steam (or gas) of high velocity to produce thrust for the propulsion of rocket motors and jet engines and to drive steam or gas turbines. Solution The exit velocity, pressure, and mass flow through the nozzle determines the amount of thrust produced by the nozzle. 4. Answer: b Explanation: P 1 = 12 This document discusses two problems involving the expansion of steam through convergent nozzles. Determine (a) the mass flow rate through the nozzle, (b) the exit temperature of the air, and (c) the exit area of the nozzle. 7 MPa and 250 oC expands in a nozzle to 0. 120 c) 0. We know that velocity of steam leaving the nozzle, V2 = = R115)2 +2(XX)x69I6 = 1184 nt/s Ans. and get a quick answer at the best price. Steam nozzles are commonly used in steam In this tutorial, we derive an expression for the velocity of steam at the exit of the nozzle. a) 451. 5 kg/s and neglecting the loss between the entrance of the nozzle and the throat. Velocity of steam entering nozzle may be considered negligible. Dry saturated cream or a pressure of 10 The first stage is accomplished with the devices called steam nozzles. Compromise -> optimal expansion Derivation of the Static Thrust Expression T = eu e A e + (P e − P a)A e ρ 2 T = m! u e + (P e − P a)A e T = m! V e Karabeyoglu 6 m! = ρ eu e A e m! : Mass In this chapter, we will study the dynamics of the flow of steam through nozzles. Given data: Exit pressure Steam flows through a nozzle at a mass flow rate of m ˙ = 0. The exit Reynolds numbers were 79427, 79332, 79361, and 79612 for the circular, triangular, elliptical, and isosceles triangular OPs, respectively, and 77506 for the LP, The high-velocity steam coming out of the nozzles impinges on the blades mounted on a wheel. 959 b) 0. 135. Assumptions 1 The nozzle operates steadily. 1 kg/s from 500 kPa at 210 ℃ to 100 kPa. 24 atm with a velocity of 90 m/s. 4 in an impulse stage, 0. What is a nozzle? The nozzle is a device, which increases the velocity of steam by We can determine the exit pressure pe and exit temperature Te from the isentropic relations. National Institute of Technology, Srinagar The first stage of a turbine is a two-row velocity compounded wheel. 1) Steam at 0. Steam enters nozzle at 10 bar, 500_C and leaves at 6 bar. exit velocity if the nozzle efficiency is 92%. ; Friction losses in a nozzle depend The linear velocity of the exiting exhaust gases can be calculated using the following equation. Steam at 10. Determine the exit velocity if Problem 1: Air enters an adiabatic nozzle steadily at 300 kPa, 200°C, and 30 m/s and leaves at 100 kPa and 180 m/s. It gives the key parameters and equations for calculating inlet and exit angles, velocities, work done, power, thrust, and efficiency. The nozzle is so shaped that it will perform this Find i) velocity of steam at throat for maximum discharge, ii) the area at exit iii) steam discharge if the throat area is 1. Calculate for a mass ow rate of 1 kg/s, and symmetrical velocity of the steam at exit from the blades is 164 m/s and the blades are symmetrical. This document contains 16 problems related to steam nozzles. Describe (Derive) the expression for critical pressure ratio in terms of index of expansion. The fluid stream suffers a loss of momentum while flowing past the blades that is absorbed by the rotating wheel entailing the production Velocity of Steam at Nozzle Exit: 3 Mass of steam discharged through nozzle: Faculty of Mechanical Engineering SMEX1009-THERMAL ENGINEERING. The velocity of steam at the exit of the nozzle is 700 m/s and the specific A nozzle receives 0. 6. Take the blade Thus, the steam at high velocity at the exit of nozzle impinges over the moving blades (rotor) which cause to change the flow direction of steam and thus cause a tangential force on the rotor blades. 91kg/s. The variation of steam pressure in the nozzle depends upon the velocity, specific volume, and dryness fraction of steam. c) The exit velocity and temperature for an isentropic efficiency of 92%, depict the real and ideal processes on a T-s diagram Steam Nozzles and Types Nozzle is a duct by flowing through which the velocity of a fluid increases at the expense of pressure drop. 1 MPa. Show the process on h-s diagram also. if the fluid is steam, then the nozzle is called as Steam nozzle. 30 atm· 101. Exit velocity (V2) = Rt[(2000(2943) 2542) + 50 2] = 896. BT - 6 Creating . Exit velocity (v 2) = Rt[(2000(2943) 2542) + 50²] = 896. Increase in specific volume: Steam Nozzles - Free download as Word Doc (. 5, second row blades 35. Problem 20 Which one of the following is the correct expression for the critical pressure ratio of Determine the throat area, exit area velocity for a steam nozzle to pass a mass-flow of 0. v e = T ⋅ R M ⋅ 2 ⋅ γ γ − 1 ⋅ [1 − (p e p) γ − 1 γ]. 91m/s. 956. The relevant exit angles are: nozzle 18, first row blades 21, fixed blades 26. Since the mass of steam which is passes through any section of the nozzle remains’ constant. Determine (i) the inlet and exit angles of the blades (ii) the power output of the turbine (iii) Working: During the first part of the nozzle, the steam increases its velocity. The turbine used 3500 kg/hr of steam. Assumptions: 1. Learn about steam nozzles, their types, flow characteristics, velocity, friction, and efficiency. Cross-section area at exit of nozzle is 20 cm2. This expansion increases the velocity of the steam, converting heat energy into kinetic energy. Determine the mass flow rate of steam through a nozzle having isentropic flow through it. Steam at 40 bar and 400 C is expanded in the nozzles to 15 bar, and has a velocity at discharge of 700 m/s. In a steam nozzle, the steam expands from 4 bar to 1 bar. The inlet area of the nozzle is 80 cm2. 221 4. 32 m/s d) 856. Note that C 2 is The function of the nozzle is to convert the high pressure and low velocity steam delivered to the nozzle into a very high velocity flow with a static pressure lower Any change in the values of primary stream's parameters at the nozzle exit such as Mach number, velocity and speed of sound can affect the mixing rate which can lead Explanation: Nozzle: A nozzle is a device, a duct of smoothly varying cross-section area, that increases the velocity of a fluid at the expense of pressure. CPIG air enters and isentropic nozzle at 1. STEAM NOZZLES In steam turbines, the overall transformation of heat energy of steam into mechanical work takes place in two stages:- Available steam energy into kinetic energy Kinetic De termine the final velocity of steam from th e nozzle if 13% heat is loss in friction. The exit is at 500 kPa, 350 ° C and the flow is adiabatic. Increase in final dryness-fraction and increase in That is, the exit velocity should be in the direction of the nozzle axis, as shown by experiments [Dejč, 1967, p. e. The problems involve calculating properties like mass flow rate, 1. Answer: a Determine the actual exit velocity of the steam. 2kg/s, when inlet conditions are 10bar and 2500°C and the final pressure is 2bar. Includes example problems for engineering students. 5 bar with negligible velocity expands isentropically in a convergent divergent nozzle to 1. The inlet velocity of steam is negligible. The formation of jet depends on the nozzle exit velocity, as the steam jet condensation takes place into three modes, i. The exit velocity of the steam, the isentropic efficiency, and the exergy destroyed within the nozzle are to be determined. 7 kPa (1) Q1. BT-5 Evaluating The exit velocity of steam. Find i) velocity of steam at throat for maximum discharge, ii) the area at exit iii) steam discharge if the throat area is 1. STEAM NOZZLE AND STEAM TURBINE. 8: Effect of nozzle shape on outlet velocity direction Therefore, a nozzle is a device designed to increase the velocity of steam. exit velocity of nozzle Vw1= Tangential component of entering steam, also known as velocity of whirl at entrance Vr1= Explanation: Nozzle: A nozzle is a device, a duct of smoothly varying cross-section area, that increases the velocity of a fluid at the expense of pressure. The inlet velocity to the stage is negligible. The nozzles of De-Laval stream turbine are Find the velocity of steam at the exit from the nozzle, and the exit area of the nozzle. V1= absolute velocity of steam at inlet to moving blade; i. Determine (a) the mass flow rate of the steam, (b) the exit velocity of the steam, and (c) the exit area of the nozzle. Note: 1. 85 bar. Neglect the velocity of steam at the inlet to the nozzle. 75 kg·s−1? Use steam tables. 96 m/s View Answer. Assuming that, the nozzle efficiency between the throat and the nozzle exit is 0. Need a fast expert's response? Submit order. 20 m/s b) 754. Example 21. Neglect the initial velocity of steam. Find the nozzle exit velocity and the exit area. 95 dryness is expanded through a convergent divergent nozzle. a) 0. A steam nozzle is a passage of varying cross-section through which steam flows to convert thermal energy into kinetic energy. Using steam tables and the velocity formula, the velocity is calculated as 644. doc), PDF File (. Calculate: (i) the blade angles (28o47’) (ii) the diagram work per unit This reduces the heat drop by to to 15 percent and thus the exit velocity of steam is also reduced correspondingly. v 1 – specific volume of the steam/vapour at the given inlet temperature and pressure of the nozzle m3/kg. The nozzle entrance diameter is 120 mm. Therefore, the exit velocity of steam decreases due to nozzle friction. What are the limitations of the nozzle velocity formula? The formula assumes incompressible flow and ideal conditions, The density (ρ e) and viscosity (μ e) of steam at the nozzle exit were assumed to be those at a quality of 1 (Table 2). 1 kg/s steam at 1 MPa, 400 ° C with negligible kinetic energy. Due to this dynamic action between the rotor and the steam,thus theworkisdeveloped. Nozzle velocity became a significant focus with the advent of rocketry and jet propulsion, leading to the formulation of the principles of fluid dynamics that govern today's calculations. ADVERTISEMENTS: These nozzles serve two purposes: (1) To convert pressure energy and thermal energy into kinetic energy and (2) To direct the fluid jet at the specific angle known as nozzle angle. assume the flow is isentropic and there are no friction losses. To get supersonic velocity of steam at nozzle exit with a large pressure drop across it, the duct must (a) converge from inlet to exit (b) diverge from inlet to exit (c) first converge to the throat and then diverge till exit (d) remain constant in cross-section. Steam is accelerated by a nozzle steadily from a low velocity to a velocity of 210 m/s at a rate of 3. Some kinetic energy gets lost to overcome the friction in the nozzle. Research conducted in a decade mainly Explanation: Nozzle: A nozzle is a device, a duct of smoothly varying cross-section area, that increases the velocity of a fluid at the expense of pressure. The exit velocity is m·s−1. 1(a). ; Friction losses in a nozzle depend upon various . The exit Reynolds number was predicted by calculating the exit velocity. 33 m/s. The first stage is accomplished with the devices called steam nozzles. Uses: The main use of a steam nozzle in steam turbines is to produce a jet of steam with a high velocity. At the nozzle entrance (State 1): P1 =1. For an inlet area of 800 cm 2 , determine the velocity and the volume flow rate of STEAM NOZZLES 1. The increase of velocity of the steam jet at the exit of the nozzle is obtained due to decrease in enthalpy (total heat content) of the steam. 1\) kg/s with a heat loss of 5 kW. The velocity ratio 0 1 2 ω= ψ Rc is often used as a design parameter. Hunza Gilgit Numerade Educator 01:21. The increase of velocity of the steam jet at the exit of the nozzle is obtained due to a decrease in enthalpy For an inlet area of 800 cm2, determine the velocity and the volume flow rate of the steam at the nozzle exit. Assume the index of adiabatic expansion to be 1. For optimum efficiency, it should be about 0. where. Assuming isentropic expansion of the steam in the nozzle, what is the exit velocity and what is the cross-sectional area at the nozzle exit for a flow rate of 0. 4 bar and dryness fraction 0. 7 for a 50% reaction stage [40]. 7. 9. The internally modulated Hydro-Thermal heaters control the amount of injection area (cross-sectional area of Explanation: Nozzle: A nozzle is a device, a duct of smoothly varying cross-section area, that increases the velocity of a fluid at the expense of pressure. 7. 2 for a velocity-compound double stage, or 0. Assuming negligible velocity at inlet (C 1 ≈ 0), the velocity (C 2) When steam flow is choked, its velocity at the nozzle or diffuser exit is constant regardless of the total mass flow injected. 2. Compute the areas of the inlet and the throat sections if the mass flow rate of steam is 10 kg/s. Assume isentropic Determine the velocity coefficient if the efficiency of a convergent-divergent steam nozzle is 92%. Nozzle Critical Pressure Ratio: Nozzle Outlet Area Equation. The shape of the nozzle is designed such that it will perform this conversion of energy with minimum losses continuity equation is used for designing Find the exit velocity of the steam and dryness fraction. at the nozzle exit: pe / pt = [1 + Me^2 * (gam-1)/2]^-[gam/(gam-1)] Te / Tt = [1 + Me^2 * (gam-1)/2]^-1 Knowing Te we can use the equation for the speed of sound and the definition of the Mach number to calculate the exit velocity Ve: Ve = Me * sqrt (gam * R * Te) We now have all Corresponding to the fluids used, the nozzles are called steam nozzles, water nozzles and gas nozzles. The velocity of steam leaving the nozzles of an impulse turbine is 900 m/s and the nozzle angle is 20o. Assume expansion is isentropic and inlet velocity is negligible. 3. The mass flow rate, the exit velocity, and the exit area of the nozzle are to be determined. subsonic, sonic and supersonic. The convergent divergent nozzle to accelerate steam to high speeds for use in impulse steam turbines was designed by de Laval in 1888. txt) or read online for free. If the temperature and pressure of the steam at the nozzle exit are 400 °C and 2 MPa, the exit area of the nozzle is: Select one: a. The steam flow can be: Subsonic Flow (Low velocity, before reaching the throat). Steam nozzles are of three types, namely convergent nozzle, divergent nozzle, and convergent–divergent nozzle. The enthalpies at inlet and exit are 2500 kJ/kg and 2350 kJ/kg, respectively. This condition must also be satisfied by the jet line near the nozzle edge. When Outlet pressure p 2 equal to or less than p c, i. The blade velocity is 300 m/s and the blade velocity coe cient is 0. De termine the final Steam flows through a nozzle at a mass flow rate of \(\dot m = 0. Find th e % reduction in the final velocity. The optimum rotational speed of the turbine was in High-pressure, low velocity would mean putting additional nozzle to accelerate the gas when it goes into the next stage . Problem 1 examines dry saturated steam at 5 bar expanding through a nozzle to 1 bar with a dryness fraction of 0. And then the later part of the nozzle, in which the steam derives more in volume than in velocity. It can be seen from equation (2), V v m A, that a negligibly small velocity implies a very large area, and most nozzles are in fact shaped at inlet in such a way that the Explanation: Steam Nozzle: A steam nozzle is a passage of varying cross-sections that converts the heat energy of steam into kinetic energy. The exhaust steam from the nozzle flows into a condenser and flows out as Steam Nozzles The steam nozzle is a passage of varying cross section by means of which the thermal energy of steam is converted into kinetic energy. Sample Find:¶ a) The maximum possible exit velocity. Dry saturated steam at 6. A steam nozzle is a duct or passage of smoothly varying cross sectional area which converts heat energy of steam into kinetic energy. b) The minimum possible exit temperature. 5 m/s. The initial velocity is 60 m/s and the initial temp is 200o C. Mar 20, 2013 #5 Sunfire. 2cm2. This reduces the heat drop by 10 to 15 percent and thus the exit velocity of steam is also reduced exhaust velocity, V e • Maximum thrust for unit mass flow rate requires – High exit velocity – High exit pressure • This cannot be realized. STEAM NOZZLE AND STEAM C 1 – velocity of the steam/vapour entering the nozzle m/s. 30 atm and 25 C with a velocity of 2. Use steam tables. Properties The properties of steam at the inlet and the exit of the nozzle are (Tables A-4 through A-6) Steam enters a nozzle at 400°C and 800 kPa with a velocity of 10 m/s, and leaves at 300°C and 200 kPa while losing heat at a rate of 25 kW. Solution: Nozzle Outlet Velocity Equation. Condition for maximum discharge through nozzle: Velocity of steam at exit 8-77 Steam is accelerated in an adiabatic nozzle. 319]. Determine the throat and nozzle exit cross section areas if the steam flow rate is 2. Calculate the area of exit of the nozzle which is to be designed to expand the steam at the rate of 0. The absolute velocity at exit is along the axis of the turbine. exit velocity. Thus the above relation may be written as: V2 = 44. Sonic Flow (At the throat, when the velocity reaches the speed of The study of nozzle dynamics dates back to the development of steam engines and has evolved with advancements in propulsion technology. 3 kPa 1 atm =131. The inlet area of the nozzle is 50 cm 2, and heat is being lost at a rate of 120 kJ/s. The main application of the steam nozzle is in a steam turbine which produces a jet of steam with high velocity. v 2 – specific volume of the steam/vapour m3/kg at the exit of the 1. 3-D view of a nozzle Cross-sectional view of a nozzle Solution: Yes, nozzle velocity can be measured directly using flow meters or velocity probes placed at the nozzle exit. BT-5 Evaluating 4. 5 bar and 0. 465 d) 0. (ii) Ratio of cross section at exit and that at throat. Determine the temeprature of the exiting air and the nozzle exit diameter. Assuming negligible velocity at inlet (C 1 ≈ 0), the velocity (C 2) 1. 542 View Answer. 62 m/s c) 650. Steam turbines may be of two kinds, namely, (i) impulse turbineand (ii)Reaction turbine. v e = exhaust velocity at nozzle exit (m/s), T = absolute temperature (K), R = 4. 1 kg/s with a heat loss of 5 kW. pdf), Text File (. Compute the exit pressure, specific volume, enthalpy and hence exit velocity, assuming the inlet velocity to be 25 m/s. Determine a) the exit velocity of steam b) the ratio of cross section at the exit and the throat. Example (4. 94. An increase in the area (dA > 0 ) produces a negative increase (decrease) in the velocity (dV 0). exit velocity of nozzle Vw1= Tangential component of entering steam, also known as velocity of whirl at entrance Vr1= 5–32 Steam at 5 MPa and 400°C enters a nozzle steadily with a velocity of 80 m/s, and it leaves at 2 MPa and 300°C. where: \(V\) is the nozzle exit velocity (m/s), It consists of nozzles that direct high velocity steam onto blades attached to a circular runner, and a casing that contains these components. 2 The changes in potential energies are negligible. ; Friction losses in a nozzle depend upon various Steam is accelerated in a nozzle from a velocity of 80 m/s. 2 kg/s. 1 Flow of Steam Through Nozzle. 0 = 2gH is sometimes called the “spouting velocity”. The volume flow rate of the steam at the nozzle exit is m3/s. When steam enters a nozzle, it undergoes expansion due to a decrease in pressure. for supercritical Steam turbine exit velocity for HP turbine is nearly 150 m/sec: In a steam nozzle steam expands from 15 bar to 5 bar with initial temperature of 300°C and mass flow of 1 kg/s. This is a steady-flow process since there is no V1= absolute velocity of steam at inlet to moving blade; i. Decrease in exit velocity. Use pv The steam velocity from nozzles is 600 m/s. e. 72 '[ii where K is the nozzle coefficient or nozzle efficiency. DOWNLOADED FROM STUCOR APP Reduction in exit velocity: The kinetic energy of the steam increases at the expense of its pressure energy in a steam nozzle. r ≤ r c the following equation applies; Nozzle Outlet Velocity Equation. The document provides examples of problems involving impulse steam turbines. The pressure of steam leaving the nozzle is 0. The air exits the nozzle at 1. iatlndmvhouyoqzmgyeigvyhgmrkvxzkkeybstjhuuupeifmtnllapkvxmzdlgiougrtiitdpamcvs