Nozzle efficiency in steam turbine INTRODUCTION Steam turbines are used in all of our major coal fired power stations to drive the generators or alternators, which produce electricity. \({\eta _{nozzle}} = \frac{{{\rm{Δ }}{h_{actual}}}}{{{\rm{Δ }}{h_{isentropic}}}}\) This set of Power Plant Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Turbine Efficiency and Flow Through Nozzles – I”. A steam nozzle may be defined as a passage of varying cross-section, through which heat energy of steam is converted to kinetic energy. [4] Oct 12, 2023 · Using the above formula, you could then calculate the nozzle isentropic efficiency as follows: \[ η_{\text{Isentropic,Nozzle}} = \frac{600}{1000} = 0. In 1878, a Swedish engineer, Carl G. P. In the case of steam turbine it is the product of nozzle efficiency, diagram efficiency and mechanical efficiency. A reaction turbine rotor blades are designed to form convergent nozzles. In most turbines, the blade wheels rotate in a space full of steam. The mean diameter of the blades is Lecture 8 : Single stage impulse turbine – de Laval turbine, Compounding of turbines: Velocity compounded impulse turbine – Curtis turbine, Pressure compounded impulse turbine – Rateau turbine. The turbine uses 3000 kg/h of steam. This parameter reduces the overall efficiency and work output. efficiency (modern steam boilers operate at approximately 80% efficiency) is well in excess of the 1. The thick-walled castings used for the pressure-containing turbine sections are called shells and are usually made from alloy steel materials. 9. 9 (70–90%). 3. Based on the steam flow angle at the nozzle outlet when the operating pressure ratio is 0. A reaction turbine uses the reaction force with the acceleration of steam through the nozzles. (4. The nozzle angle is 20° and the steam velocity from the nozzle is 600 m/s. As the steam jet changes direction with striking the bucket-like shaped rotor Applications of Nozzles 1) Steam and Gas turbines, 2) Jet engines, 3) For propulsion of rocket motors, 4) Flow measurements, 5) In injectors for pumping water , 6) In ejectors for removing air from condensers . A steam turbine is basically an assembly of nozzles fixed to a stationary casing and rotating blades mounted on the wheels attached on a shaft in a row-wise manner. Over the years, advancements in materials, design, and technology have contributed to notable improvements in steam turbine efficiency. The main use of steam nozzle in steam turbines is to produce a jet of steam with a high velocity. Figure 2: Steam consumption diagram for throttle control and nozzle group control 5 Analysis of the steam turbine operation Mar 7, 2015 · 2. CATIA software is used for the modeling of all shapes and CFD analysis was executed by using ANSYS FLUENT. E. At entry to the turbine, the steam gains kinetic energy by passing through a nozzle (a fixed nozzle in an impulse type turbine or the fixed blades in a reaction type turbine). A common assumption in analyzing nozzle flow is that it's an isentropic process. Therefore, a condenser steam turbine is more efficient than a back-pressure (non-condensing) steam turbine despite rejecting heat through a condenser. For power generation purposes, a typical condensing turbine may achieve operating efficiencies between 30-40%, compared to a non-condensing turbine which may achieve 15-35% . The resulting power generation . The problems require using velocity triangles and equations related to impulse turbine operation to Exercise Problems (for Steam Turbines) Q1. The first stage is accomplished with the devices called steam nozzles. 1 KJ/kg of steam. These parameters describe how efficiently a turbine, compressor, or nozzle approximates a corresponding isentropic device. Nozzle efficiency: Nozzle efficiency can be defined in the following ways. These nozzles are designed to expand the steam, increasing its velocity as it passes through, which is essential for driving the turbine blades and generating power. A steam turbine has two different types: Impulse reaction turbine; Reaction steam turbine; Both types of steam turbines work on different principles (as discussed above). a) 65. It asks the reader to calculate various parameters such as blade angles, power developed, axial thrust, and diagram efficiency given information about the steam conditions, nozzle angles, blade speeds, and other specifications. The document then discusses concepts like Mach number and Aug 31, 2024 · Efficiency Optimization: Efficient steam nozzles maximize the conversion of thermal energy into mechanical work, enhancing the turbine’s overall efficiency. At the heart of the system lies the rotor assembly, consisting of a turbine shaft with attached blades or vanes. That sounds poor, but it's about three stage losses. Calculating the isentropic values x= Sˆ in −Sˆ l Sˆ v −Sˆ l Sˆ out =Sˆ in Steam η turbine = W! s-actul W! s-isentropic = ΔHˆ ΔHˆ isentrpc ΔSˆ=0 5 E82 6 To calculate the outlet enthalpy Hˆ out The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and h d = Enthalpy or heat drop during expansion of steam in a nozzle) A) V = 44. Creep and Dishing Mar 25, 2016 · 2. STEAM NOZZLES AND TURBINES . These parameters describe how efficiently a turbine, compressor or nozzle approximates a corresponding isentropic device. PATIL Steam Nozzles and Turbines Steam Nozzle: A steam nozzle is a passage of varying cross-sectional area in which heat energy of the steam is converted into kinetic energy. In impulse turbine velocity (or kinetic energy) of steam increases in nozzle while this work is to be done by fixed blades in the reaction turbine. A simple impulse turbine has a mean blade speed of 250 m/s. J. ) A real turbine has a turbine efficiency, that compares its performance with that of an isentropic turbine. When steam f lows through a nozzles expansion process take place. The nozzles are just located just before the steam turbines. Types of Turbines or Expanders (cont. Determine the amount of energy converted to heat by blade friction if the blade friction factor is 0. The effect of partial admission creates eddies in the blade channels. In a two-step pressure velocity compounded turbine, the first pressure drop occurs in the first set of nozzles, the resulting gain in the Fixed nozzles in an impulse turbine lead the steam flow into high-speed jets with significant kinetic energy. undivided solid ring. org) Reaction Turbine. de Laval developed a simple impulse turbine, using a convergent-divergent (supersonic) nozzle which STEAM TURBINES Steam N0zzles 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 energy into mechanical work. Jan 11, 2004 · Steam Turbine의 중요한 역할 중 하나는 전체 Plant의 Steam Balance를 맞추는 것이다. In steam turbines, nozzles are used to direct high-pressure steam onto the blades, driving the turbine shaft and generating power. 5 and mean blade velocity 150 m/ asked Mar 2, 2022 in General by Anuragk ( 237k points) This ratio is known as the Isentropic Turbine/Compressor/Nozzle Efficiency. 075 bar. 13. Construction of steam nozzle If great pressure differences exist in front and at the back of inlet nozzles of steam turbines a secure attachment of the nozzles is sometimes rather difficult. The main function of steam nozzle in steam turbines is to produce a jet of steam with a high velocity. The valve points can be adapted to the main design points of the turbine system by specifying nozzle areas for each nozzle group. Key Words: steam turbine nozzle, CATIA, ANSYS FLUENT 1. LP / MP Steam을 얻기 위해 Control Valve, 또는 Condenser를 두는 방법도 있지만 열효율적인 측면에서 볼 때 낭비가 크므로,Steam Turbine의 Extraction, Admission을 이용하여 Down stream의 Steam을 일로 사용한다. Lecture 9 : Axial flow reaction turbine: Reaction principle, Degree of reaction, Velocity triangles, Fixed blade/nozzle efficiency, Moving blade . Due to the effect of blade friction loss, the relative velocity at outlet is reduced than the relative velocity at inlet. NOZZLE – A duct of smoothly varying cross-sectional area in which a steadily flowing fluid can be made to accelerate by a pressure drop along the duct. The turbine used 3500 kg/hr of steam. In order to ensure high-efficiency turbine designs without sacrificing turbine reli-ability, it is necessary to use both highly-efficient nozzle and bucket designs to minimize profile and secondary losses, and advanced clearance controls to minimize leakage flows. Sample problems are worked through step-by-step showing calculations for impulse turbine performance parameters like blade angles, relative velocities, forces, power, and STEAM TURBINES Steam N0zzles 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 energy into mechanical work. turbine casing, and having its outer periphery shrunk against the inner casing without making use of a special guide wheel body. Calculate the mass flow rate of steam, power developed and stage efficiency. Steam first enters into the turbine at superheated state. 90. Economically, however, the turbine generates power at the efficiency of the steam boiler. • Computation of performance parameters for design and off design nozzles • Calculation of dimensions of nozzles, operating principles of impulse and reaction turbines • Reasons and methods of turbine compounding • Calculation of diagram power, diagram efficiency, stage efficiency of turbines using trigonometric principles and namic performance of the steam turbine is pri-marily determined by steam path components, including the valves, inlet, nozzles, buckets, steam leakage control devices and the exhaust. turbine is found to be more efficient than the three-row type. Frictional resistance is offered during the flow of steam through nozzles on moving and stationary blades. GE’s development effort has been underway for Lecture 20: Problem Solving (Nozzles and diffusers) Download Verified; 21: Lecture 21: Steam Turbine: Download Verified; 22: Lecture 22: Compounding of Steam Turbine: Download Verified; 23: Lecture 23: Impulse Steam Turbine: Download Verified; 24: Lecture 24: Impulse Steam Turbine Performance: Download Verified; 25: Lecture 25: Problem solving Apr 14, 2023 · The isentropic heat drop in the nozzle of an impulse steam turbine with nozzle efficiency 0. It results into reduction in the useful enthalpy drop. 2. 50 kJ c) 45. Flow of steam through nozzles: The flow of steam through nozzles may be regarded as adiabatic expansion. 9, blade velocity ratio 0. There are three main types of nozzles used in steam turbines: convergent, divergent, and convergent-divergent. 1 Introduction to steam turbine nozzle Nozzles are wont to guide the steam to hit the moving blades and to convert the pressure energy into the K. The smalls section of the nozzle is known as throat. Oct 27, 2020 · Nozzle: Nozzle is a duct that increases the velocity of the flowing fluid at the expense of pressure drop. It is the ratio of actual enthalpy drop to the isentropic enthalpy drop. valve losses are evident in the slightly higher steam consumption for the nozzle group control. 72 K h d Jul 29, 2016 · To design a more efficient steam turbine, a casing with proper nozzles and vanes to confine the steam and valves to control the admission of steam to the nozzles should be used. MR. The energy lost in friction reheats the steam and the quality of steam at exit from the stage gets improved. The steam leaves the nozzle at a _____ a) low pressure and a high velocity b) high pressure and a high velocity c) high pressure and a low velocity d) low pressure and a low velocity View Answer The steam velocity from nozzles is 600 m/s. 32 kJ Mar 2, 2022 · The isentropic heat drop in the nozzle of an impulse steam turbine with nozzle efficiency 0. The radial turbine differs from the axial one in that, in the nozzle unit and in the greater part of the rotor, the working fluid moves in the plane perpendicular to the axis of rotation. Nozzle failures are often due to erosion, corrosion, or thermal stresses, necessitating regular inspections to identify and address these issues. When the steam leaves the nozzle it is moving at high velocity towards the blades of the turbine rotor. TYPES OF STEAM NOZZLES 9/12/2023 2 How pressure decreases and velocity increases in divergent section 9/12/2023 3 Introduction to Steam Nozzles 1. Steam turbines convert the high-pressure, high-temperature steam from a steam generator into rotational shaft work. The steam turbine's rotor plays a crucial role in its efficiency in generating steam. The adiabatic enthalpy drop in a given stage of a multi-stage impulse turbine is 22. The maximum blade velocity is 320 m/s and the nozzle efficiency in all stages is 0. The document then discusses concepts like Mach number and The document contains several problems related to impulse turbines. It covers the classification and construction of steam turbines, as well as the components and working of steam nozzles. Therefore, these have different efficiency, but the below-given formula can calculate the efficiencies of these turbines: Thermodynamically, steam turbines achieve an isentropic efficiency of 20% to 70%. 5 and mean blade velocity 150 m/s in kJ/kg is This question was previously asked in Feb 2, 2011 · In axial turbines (), the working fluid moves mainly along co-axial surfaces parallel to the turbine axis. Reheating cycle of steam turbine. Types of Steam Nozzle: 1. A well designed nozzle converts the heat energy of steam into kinetic energy with a minimum loss. 6 \text{ or } 60\% \] Unlike compressors or turbines, nozzles are designed for a different purpose and hence their performance is gauged differently, focusing more on the kinetic energy change Assumptions:¶ 1) open system, 2) steady state, steady flow (SSSF) 3) adiabatic (no heat transfer to the surroundings), 4) air is an ideal gas, 5) negelect changes in potential energy, 6) no work, 7) internally reversible process for parts a and b May 22, 2019 · This ratio is known as the Isentropic Turbine/Compressor/Nozzle Efficiency. Nozzles are used to produce high velocity steam jets to drive Steam nozzles find extensive applications in various engineering domains, including steam turbines, jet engines, and rocket motors. Nozzle failures are common in steam turbines. As the steam expand there is drop in pressure and enthalpy of steam and consequently its velocity and specific volume both increases . The viscous friction at the wheel surface causes admission losses as steam passes from nozzle to wheel. These components work together to harness the power of steam and transform it into rotational energy. To maximize power plant efficiency, aerodynam-ic and steam leakage losses in the turbine steam path must be minimized in both the rotating and stationary components. 11. It gives the key parameters and equations for calculating inlet and exit angles, velocities, work done, power, thrust, and efficiency. Oct 23, 2022 · Nozzle: Nozzle is a duct that increases the velocity of the flowing fluid at the expense of pressure drop. Determine (i) the inlet and exit angles of the blades (ii) the power output of the turbine (iii) the diagram efficiency and (iv) the end thrust per kg of steam per second and its direction (AU-May produce a jet of steam of high velocity for the purpose of driving steam turbine. The design and efficiency of the Steam turbines are particularly effective in generating energy because they produce circular motion and are responsible for over 80% of the world's energy generation. Convergent-divergent nozzles are widely used today. This will increase its expansion ratio and steam has become wet condition at the end of Dec 1, 2023 · Improving the efficiency of steam turbines is a major focus in power generation, as even small gains can lead to significant reductions in fuel consumption and greenhouse gas emissions. Nov 13, 2022 · The efficiency of impulse turbine (Reference: en. - The steam has a very ANALYSIS OF DIFFERENT TYPES OF REGULATION AND ITS EFFICIENCY Reaction turbine (No nozzle is present in reaction turbine). 32 kJ b) 30. So the useful or effective enthalpy-drop is less than isentropic enthalpy drop. In this system,the steam's ability to work may be slightly increased by reheating the steam during its passing through the turbine. However, since such turbines are relatively primitive and not very efficient, almost all turbines in operation today are a combination of reaction and impulse turbines. These losses are directly affected by the turbines output as well as its efficiency. Practically 100% gross efficiency is not possible for any turbine. The nozzle outlet angle is and the efficiency of the nozzle, defined as the ratio of the actual gain of kinetic energy in the nozzle to adiabatic heat drop, is 92%. Now steam's pressure and temperature is improved by efficiency of Rankine cycle. 6 \text{ or } 60\% \] Unlike compressors or turbines, nozzles are designed for a different purpose and hence their performance is gauged differently, focusing more on the kinetic energy change Document CHAPTER 4_ STEAM TURBINESi. \({\eta _{nozzle}} = \frac{{{\rm{Δ }}{h_{actual}}}}{{{\rm{Δ }}{h_{isentropic}}}}\) Aug 14, 2024 · This section will delve into the role of flow nozzles in optimizing turbine efficiency, the importance of fuel nozzle repair, and best practices for maintaining steam turbines to ensure optimal performance and durability. within the case of small turbine, the nozzles are located within the lower half the casing. Nozzle angles will be 15 for impulse stages and 25 for reaction stages. Dec 10, 2023 · Using the above formula, you could then calculate the nozzle isentropic efficiency as follows: \[ η_{\text{Isentropic,Nozzle}} = \frac{600}{1000} = 0. 38, the change of steam flow angle at the outlet of the conventional nozzle and supersonic nozzle is analyzed. Advanced Technologies: Variable Geometry Nozzles: Allow for adjustments in nozzle shape and size based on operating conditions, providing flexibility and maintaining optimal performance How to Calculate Steam Turbine Efficiency. 7 to 0. But this loss can be minimized through some process. The document provides examples of problems involving impulse steam turbines. for Impulse turbine and the influence of blade efficiency on the steam speed in a single stage Impulse turbine can be obtained by considering corresponding velocity diagrams as shown in Fig. All stages operate close The efficiency and reliability of a steam turbine depend on its well-designed components. Steam Turbines Performance: In steam turbines when steam flows over the blades, the friction takes place. But within the case of the larger turbine, the nozzles are located on the upper half the casing. In impulse turbine pressure falls in nozzle while in reaction turbine in fixed blade boiler pressure falls. 86. The absolute velocity at exit is along the axis of the turbine. pdf, Subject Mechanical Engineering, from University of KwaZulu-Natal- Westville Campus, Length: 36 pages, Preview: CHAPTER 4 STEAM TURBINES AND AUXILIARIES 2024 _ CPUT 1 CONTENT • Operating principles of gas and steam nozzle. 1. Steam nozzles use the expansion of steam to convert pressure energy into kinetic energy via convergent, divergent, or convergent-divergent nozzle designs. For turbines, the value of η T is typically 0. 4. When turbine works, some factors have reduced the output of the turbine, known as the losses in steam turbine or internal loss in the turbine. In steam turbines it is steam exiting nozzles that produces torque, where one of the earliest known steam turbines, described by Hero around 100 BC [3], was a reaction turbine. 4 kg/s; 41 kW) A steam turbine is to operate between 140 bar, 560 C and 0. Steam turbine nozzles are critical components in a steam turbine system that control the flow of steam from the boiler to the turbine blades, converting thermal energy into mechanical energy. Mar 8, 2025 · Contents • Operating principles of gas and steam nozzle. PREREQUISITE DISCUSSIONS . The turbines extract steam from the middle stage of condensing turbine after adjusting pressure by the control valve and utilize steam and exhaust steam as utility steam for works and others. This document discusses steam turbines and steam nozzles. A steam turbine converts the energy of high-pressure, high-temperature steam produced by a steam generator into shaft work. wikipedia. P. The blade outlet angle is 25°. Compared to steam engines, steam turbines exhibit significantly Dec 1, 2023 · The change of steam flow angle at the nozzle outlet will have an important influence on the off-design operation of the governing stage. May 7, 2023 · Although steam turbines are very efficient, they're not perfect (nothing ever is): really good ones come in at about 80–90 percent, while coal-fired steam-turbine plants as a whole capture perhaps 30–35 percent of the energy from the incoming steam and waste the rest at various stages of the process. Divergent nozzle: The crossectional area of the duct increases from inlet to the outlet then it is called as divergent nozzle. (1)When a large amount of utility steam of one or more types is required, (2)When the power demand is less than the amount of utility steam. Nozzles direct steam flow onto turbine blades, and damage or blockage can disrupt the steam path, causing vibration and blade resonance. rnij jbmnq tneyql jld ypvn tco kpran gcc iedto slkqg