Influence of Deposit on the Flow in a Turbine Cascade

1988 ◽  
Vol 110 (4) ◽  
pp. 512-519 ◽  
Author(s):  
A. Bo¨lcs ◽  
O. Sari
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Side Wall ◽  
Boundary Layer Separation ◽  
Turbine Cascade ◽  
Flow Conditions ◽  
Choked Flow ◽  
Time Marching ◽  
Mach Numbers ◽  
Laser Holography

An experimental study on a gas turbine cascade operating under transonic flow conditions is presented. The flow is compared for airfoil shapes corresponding to the design geometry and the geometry taken from a rotor blade, in an industrial gas turbine burning heavy oil, after a few thousand hours of operation. Steady-state data have been obtained in a linear cascade over a range of isentropic exit Mach numbers from 0.6 to 1.6. The flow field was determined by static pressure measurements on the side walls up- and downstream of the cascade, on one side wall in the blade passage, and on the blade surface at midspan. Furthermore, the flow was visualized by the methods of Schlieren and laser holography. The results show that the choked flow conditions are reached at different steady-state isentropic outlet Mach numbers for the two blade shapes. The deposit, typical for a gas turbine, does not however significantly modify the boundary layer separation point. The flow visualization indicates that the shock wave fluctuations have not been significantly influenced by the important roughness and thickness of the deposit. The experimental results on the two cascades are also compared with two-dimensional time-marching calculations after Denton. In the subsonic regime, good agreement was found for the “clean” blade. For the profile with deposit, the flow cannot be correctly predicted by the time-marching calculation, even in subsonic flow condition. The sonic line calculated by the numerical model under transonic outlet conditions (0.9 < M2S < 1.20) does not agree with the laser holography measurements for either of the two cascades.

scholarly journals Periodicity and Repetivity of Unsteady Measurements of an Annular Turbine Cascade at Off Design Flow Conditions

1993 ◽  
Author(s):  
A. Bölcs ◽  
H. Körbächer
Keyword(s):  
Steady State ◽  
Test Data ◽  
Separation Bubble ◽  
Incidence Angle ◽  
Leading Edge ◽  
Design Flow ◽  
Turbine Cascade ◽  
Flow Conditions ◽  
Suction Surface ◽  
Shock Region

A two-dimensional section of a gas turbine cascade has been investigated experimentally in an annular non-rotating cascade facility as regards to its steady-state and time-dependent aerodynamic characteristics at off-design flow conditions. The blades vibrated in the first traveling wave bending mode. Steady-state and unsteady data were obtained for an off-design incidence angle of about 22° and for an isentropic outlet Mach number of M2s=1.19. At this flow condition, a separation bubble was present on the suction surface close to the leading edge. A shock appeared at trans- and supersonic outlet flow conditions on the suction surface. The data showed high unsteady loads close to the leading edge and in the shock region. It was found that the steady and the unsteady pressures in the shock region on the blade surface seemed to be very sensitive to small changes in the flow conditions. The periodicity and repetitivity of the steady and the unsteady pressures (σ=180°) was checked at several circumferential channel positions. This was done to figure out to which extend test data obtained in an annular ring channel can serve as a basis for the comparison with numerically obtained data. The aim of this paper is to show where problems may arise when comparing calculated results with test data.

An Experimental Study on the Transport of Sediment in Sewer Pipes with a Permanent Deposit

1992 ◽  
Vol 25 (8) ◽  
pp. 115-122 ◽  
Author(s):  
G. S. Perrusquía
Keyword(s):  
Experimental Study ◽  
Critical Shear Stress ◽  
Side Wall ◽  
Bedload Transport ◽  
Flow Conditions ◽  
Sewer Pipes ◽  
Sediment Bed ◽  
Concrete Pipe ◽  
Geometric Factors ◽  
Particle Parameters

An experimental study of the transport of sediment in a part-full pipe was carried out in a concrete pipe. The experiments were confined to bedload transport. The purpose of this study was to analyze the flow conditions that characterize the stream traction in pipe channels and their relationship to flow resistance and sediment transport rate. Three procedures used in this kind of experimental study were tested and found valid: 1) the vertical velocity distribution near the sediment bed can be described by the velocity-defect law, 2) the side wall elimination procedure can be used to compute the hydraulic radius of the sediment bed, and 3) the critical shear stress of the sediment particles can be obtained by using Shields' diagram. A relationship to estimate bedload transport, based on dimensional analysis, was proposed. This was expressed in terms of both flow and particle parameters as well as geometric factors. Further experimental work is recommended before this relationship can be fully incorporated in a simulation model for the analysis of storm sewers.

Impact of Different Film-Cooling Modes at Trailing Edge on the Aerodynamic Performance of Heavy Duty Gas Turbine Cascade

2011 ◽  
Vol 84-85 ◽  
pp. 259-263
Author(s):  
Xun Liu ◽  
Song Tao Wang ◽  
Xun Zhou ◽  
Guo Tai Feng
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Large Mass ◽  
Turbine Cascade ◽  
Heavy Duty ◽  
Trailing Edge ◽  
Central Difference ◽  
Adiabatic Effectiveness ◽  
Heavy Duty Gas Turbine ◽  
The Impact

In this paper, the trailing edge film cooling flow field of a heavy duty gas turbine cascade has been studied by central difference scheme and multi-block grid technique. The research is based on the three-dimensional N-S equation solver. By way of analysis of the temperature field, the distribution of profile pressure, and the distribution of film-cooling adiabatic effectiveness in the region of trailing edge with different cool air injection mass and different angles, it is found that the impact on the film-cooling adiabatic effectiveness is slightly by changing the injection mass. The distribution of profile pressure dropped intensely at the pressure side near the injection holes line with the large mass cooling air. The cooling effect is good in the region of trailing edge while the injection air is along the direction of stream.

Aerodynamics of Cooling Jets Introduced in the Secondary Flow of a Low-Speed Turbine Cascade

1990 ◽  
Vol 112 (3) ◽  
pp. 539-546 ◽  
Author(s):  
F. Bario ◽  
F. Leboeuf ◽  
A. Onvani ◽  
A. Seddini
Keyword(s):  
Secondary Flow ◽  
Side Wall ◽  
Velocity Fields ◽  
Measuring Apparatus ◽  
Flow Ratio ◽  
Turbine Cascade ◽  
Hot Wire ◽  
Local Pressure ◽  
Low Speed ◽  
Jet Behavior

The aerodynamic behavior of cold discrete jets in a cold secondary flow is investigated. Configurations including single jets and rows of jets are studied. These jets are introduced through the side wall of a low-speed nozzle turbine cascade. The experimental setup and the jet behavior are fully described. The effects of location with respect to the blades, mass flow ratio, yaw, and incidence angles on the aerodynamics of single jets are investigated. The influence of neighboring jets is detailed in the case of multiple jet configurations. The interaction with the secondary flow is presented. The local pressure and velocity fields, trajectories, and visualizations are discussed. The measuring apparatus includes a five-hole probe and a hot wire for intermittency measurements.

scholarly journals Off-Design Behavior Analysis and Operating Curve Design of Marine Intercooled Gas Turbine

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Nian-kun Ji ◽  
Shu-ying Li ◽  
Zhi-tao Wang ◽  
Ning-bo Zhao
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Optimization Design ◽  
Three Dimensional ◽  
Operational Flexibility ◽  
Modeling And Analysis ◽  
Additional Degree ◽  
Performance Space ◽  
Mechanical Constraints ◽  
Steady State Model

The intercooled gas turbine obtained by adopting an indirect heat exchanger into an existing gas turbine is one of the candidates for developing high-power marine power units. To simplify such a strong coupled nonlinear system reasonably, the feasibility and availability of qualifying equivalent effectiveness as the only parameter to evaluate the intercooler behavior are investigated. Regarding equivalent effectiveness as an additional degree of freedom, the steady state model of a marine intercooled gas turbine is developed and its off-design performance is analyzed. With comprehensive considerations given to various phase missions of ships, operational flexibility, mechanical constraints, and thermal constraints, the operating curve of the intercooled gas turbine is optimized based on graphical method in three-dimensional performance space. The resulting operating curve revealed that the control strategy at the steady state conditions for the intercooled gas turbine should be variable cycle control. The necessity of integration optimization design for gas turbine and intercooler is indicated and the modeling and analysis method developed in this paper should be beneficial to it.

Research on Matching Characteristics of Ship-Engine-Propeller of COGAG

2021 ◽  
Author(s):  
Zhitao Wang ◽  
Jiayi Ma ◽  
Haichao Yu ◽  
Tielei Li
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Research Work ◽  
Simulation Models ◽  
Operating Characteristics ◽  
Modular Modeling ◽  
Steady State Operation ◽  
Pitch Ratio ◽  
Main Engine

Abstract The combined gas turbine and gas turbine power propulsion device (COGAG power propulsion device) is an advanced combined power system, which uses multiple gas turbines as the main engine to drive propellers to propel the ship. COGAG power propulsion device has high power density, excellent stability and maneuverability, it receives more and more attention in the field of ship power at home and abroad. This article takes the COGAG power propulsion device as the research object, uses simulation methods to study its steady-state operating characteristics, and conducts a ship-engine-propeller optimization matching analysis based on economy and maneuverability. The research work carried out in this article is as follows. Firstly, according to the structural relationship between the various components and the system thermal cycle mode of the COGAG power propulsion device, establish the controller, main engine, gear box, clutch, shafting, propeller, ship and other components and simulation models of the system with the modular modeling idea. Secondly, divide the gears according to ship speed. For the four working modes of single-gas turbine with load, dual-gas turbine with load, three-gas turbine with load, and four-gas turbine with load, analysis the ship-engine-propeller optimization matching of the COGAG power propulsion device based on economy and maneuverability, and calculate the best shaft speed and propeller pitch ratio in each gear, so as to obtain the steady-state operation characteristics of the COGAG power propulsion device based on the ship-engine-propeller matching, which provides a basis for determining the target parameters of the dynamic process.

Effect of Divergence Angle on Flow Through Inlet Section of Diffuser of a Gas Turbine Combustion Chamber: The CFD Approach

2006 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Jitendra Chaudhary ◽  
Zoeb Lakdawala ◽  
Hitesh Solanki ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Total Pressure ◽  
Divergence Angle ◽  
Velocity Head ◽  
Turbine Engine ◽  
Inlet Velocity ◽  
Pressure Losses ◽  
Flow Through ◽  
Mach Numbers

In the combustor inlet diffuser section of gas turbine engine, high-velocity air from compressor flows into the diffuser, where a considerable portion of the inlet velocity head PT3 − PS3 is converted to static pressure (PS) before the airflow enters the combustor. Modern high through-flow turbine engine compressors are highly loaded and usually have high inlet Mach numbers. With high compressor exit Mach numbers, the velocity head at the compressor exit station may be as high as 10% of the total pressure. The function of the diffuser is to recover a large proportion of this energy. Otherwise, the resulting higher total pressure loss would result in a significantly higher level of engine specific fuel consumption. The diffuser performance must also be sensitive to inlet velocity profiles and geometrical variations of the combustor relative to the location of the pre-diffuser exit flow path. Low diffuser pressure losses with high Mach numbers are more rapidly achieved with increasing length. However, diffuser length must be short to minimize engine length and weight. A good diffuser design should have a well considered balance between the confliction requirements for low pressure losses and short engine lengths. The present paper describes the effect of divergence angle on diffuser performance for gas turbine combustion chamber using Computational Fluid Dynamic Approach. The flow through the diffuser is numerically solved for divergence angles ranging from 5 to 25°. The flow separation and formation of wake regions are studied.

scholarly journals Fuel cell–gas turbine hybrid system design part I: Steady state performance

2014 ◽  
Vol 257 ◽  
pp. 412-420 ◽  
Author(s):  
Dustin McLarty ◽  
Jack Brouwer ◽  
Scott Samuelsen
Keyword(s):  
Steady State ◽  
Fuel Cell ◽  
System Design ◽  
Gas Turbine ◽  
Hybrid System ◽  
Steady State Performance
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