Effect of Nozzle-Rotor Clearance on Turbine Performance

2006 ◽  
Author(s):  
Eunhwan Jeong ◽  
Pyun Goo Park ◽  
Sang Hun Kang ◽  
Jinhan Kim
Keyword(s):  
High Pressure ◽  
Numerical Analysis ◽  
Pressure Loss ◽  
Performance Test ◽  
Stagnation Pressure ◽  
Operating Conditions ◽  
Impulse Turbine ◽  
Cold Air ◽  
Turbine Performance ◽  
Axial Clearance

This paper presents the results of performance test and numerical analysis of a supersonic impulse turbine. The test has been conducted using high pressure cold air. The overall turbine performance and turbine nozzle behavior for various operating conditions have been investigated. Experiment and numerical analysis also have been conducted to investigate the nozzle-rotor clearance effect on the turbine performance. It has been found that turbine performance degrades with increasing the axial clearance and this phenomenon is mainly due to the increased stagnation pressure loss in the axial clearance region.

Experimental and Numerical Study on Pressure Losses and Flow Fluctuations in a High-Pressure Valve Assembly of Steam Turbine Governing System

2020 ◽  
Author(s):  
Vaclav Slama ◽  
Lukas Mrozek ◽  
Bartolomej Rudas ◽  
David Simurda ◽  
Jindrich Hala ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Numerical Simulations ◽  
Pressure Loss ◽  
Operational Reliability ◽  
Operating Conditions ◽  
The Real ◽  
Pressure Losses ◽  
Flow Fluctuations ◽  
Valve Assembly

Abstract Aerodynamic measurements and numerical simulations carried out on a model of a high-pressure valve assembly used for nozzle governing of a turbine with 135MW output are described in this paper. Aim of the study is to investigate effects of control valve’s strainers on pressure losses and unsteadiness in the flow field. It is an important task since undesirable flow fluctuations can lead to operational reliability issues. Measurements were carried out in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences (IT) where an aerodynamic tunnel is installed. Numerical simulations were carried out in the Doosan Skoda Power (DSP) Company using ANSYS software tools. The experimental model consists of one of two identical parts of the real valve assembly. It means it consists of an inlet pipeline, a stop valve, a valve chamber with two independent control valves, its diffusers and outlet pipelines. The numerical model consists of both assembly parts and includes also an A-wheel control stage in order to simulate the real turbine operating points. The different lifts of the main cone in each control valve for its useful combinations were investigated. Results were evaluated on the model with control valve’s strainers, which were historically used in order to stabilize the flow, and without them. The results of the experimental measurement were compared with the numerical results in the form of pressure losses prediction. From measured pressure fluctuations, it was found out where and for which conditions a danger of flow instabilities occurs. It can be concluded that there is a border, in terms of operating conditions, where the flow field starts to be unstable and this border is different dependent of the fact whether the control valve’s strainers are used or not. Therefore, the areas of safe and danger operational reliability can be predicted. The influence of the control valve’s strainers on the maximal amplitude of periodic fluctuations appears only for the cases when valves are highly overloaded. For normal operating conditions, there is no difference. As a result, the control valve’s strainers do not have to be used in standard applications of valve assemblies. Furthermore, a loss model for valve pressure loss estimation could be updated. Therefore, a pressure loss should be predicted with a sufficient accuracy for each new turbine bid with similar valve assemblies.

High Pressure CO2 Compressor Testing for Tupi 1, Tupi 2, and Tupi 3

2012 ◽  
Author(s):  
Gary M. Colby ◽  
Timothy R. Griffin ◽  
Manoj K. Gupta ◽  
Harry F. Miller ◽  
Steven E. Nove ◽  
...  
Keyword(s):  
High Pressure ◽  
Performance Test ◽  
Mechanical Test ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Actual Process ◽  
Process Gas ◽  
High Pressure Co2 ◽  
Hydrocarbon Gas ◽  
Design And Manufacture

This paper describes the mechanical and aerodynamic testing of the high-pressure CO2 compressors for the Tupi I, Tupi II, and Tupi III projects. This includes the results of the API 617 mechanical test and a special magnetic bearing exciter test to demonstrate rotordynamic stability at design operating conditions, as well as the results of the ASME PTC-10 Type 2 inert gas performance test and the ASME PTC-10 Type 1 full load–full pressure test on a CO2–hydrocarbon gas mixture equivalent to the actual process gas. A brief description of the compressor design and manufacture is also presented.

Experimental and Numerical Analysis of the Secondary Flow Across the Interphase Balance Drum of a High Pressure Back-to-Back Centrifugal Compressor

2017 ◽  
Author(s):  
Carmine Carmicino ◽  
Francesco Maiuolo ◽  
Emanuele Rizzo
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Numerical Analysis ◽  
Pressure Distribution ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Local Pressure ◽  
Flow Angle ◽  
One Dimensional ◽  
Honeycomb Seal

With the major aim of gathering information on the machine lateral stability in high pressure-high density conditions, and of assessing the prediction capabilities of the in-house design tools and overall process, a back-to-back centrifugal compressor has been instrumented and tested in several operating conditions. The present paper focuses on the secondary flows across the interphase balance drum of the back-to-back compressor, where the sealing is accomplished with a honeycomb seal. The compressor interphase section has been instrumented with dedicated special probes for the clearance measurement associated to pressure and flow angle probes in order to characterize pressure distributions and swirl variations depending on the specific operating range. The experimental data acquired over the machine operation have been compared with a three-dimensional steady-state numerical analysis results obtained from the simulation, carried out with a Reynolds averaged Navier-Stokes (RANS) approach, of the flowfield in the complex interphase secondary system composed by the impeller cavities and the honeycomb seal. This paper addresses the comparison between numerical results and experimental data, which allowed the matching of models with experiments in terms of pressure distribution and the complex flowfield. Finally, all the data have been used to validate an in-house one-dimensional flow network solver for pressure distribution and leakage flow calculations along cavities and seals. Results have shown a general good agreement between measured data and calculation output. In particular, computational fluid dynamic analysis provided detailed pressure and velocity distributions that allowed gaining insight in the physics of such a complex region. The one-dimensional model has been demonstrated to be a fast and reliable tool to well predict local pressure variations inside cavities and seals and, consequently, the residual axial thrust.

scholarly journals Numerical Analysis of Bi-directional Impulse Turbine Performance for Thermoacoustic Power Generators

2019 ◽  
Vol 158 ◽  
pp. 1986-1992 ◽  
Author(s):  
Dongdong Liu ◽  
Yanyan Chen ◽  
Wei Dai ◽  
Ercang Luo
Keyword(s):  
Numerical Analysis ◽  
Impulse Turbine ◽  
Power Generators ◽  
Turbine Performance

Experimental and Numerical Investigations of Aerodynamic Behavior of a Three-Stage HP-Turbine at Different Operating Conditions

2010 ◽  
Author(s):  
S. A. Abdelfattah ◽  
M. T. Schobeiri
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Operating Conditions ◽  
Numerical Investigations ◽  
Turbine Performance ◽  
Speed Range ◽  
Three Stages

This paper describes experimental and numerical investigations of a three-stage high pressure research turbine which incorporates fully 3-D bowed blades at various operating conditions. Experimental data were obtained using interstage aerodynamic measurements at three measurement stations, namely, downstream of the first rotor row, the second stator row and the second rotor row. Measurements were conducted through the use of five-hole probes traversed in both circumferential and radial directions to create a measurement window. Aerodynamics measurements were carried out within a rotational speed range of 1800 to 2800 RPM. Numerical simulation of the aforementioned turbine was performed through the use of a commercial computational fluid dynamics code. A detailed mesh of the three-stages was created and used to simulate the corresponding operating conditions and a comparison was made between experimentally and numerically determined aerodynamics and turbine performance.

Influence of Tailored Boundary Layer Suction on Aerodynamic Performance in Bowed Compressor Cascades

2017 ◽  
Author(s):  
Ding Jun ◽  
Du Xin ◽  
Chen Shaowen ◽  
Zhou Xun ◽  
Wang Songtao ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Stagnation Pressure ◽  
Operating Conditions ◽  
Design Parameters ◽  
Computational Domain ◽  
Separation Region ◽  
Boundary Layer Suction

The impact of boundary layer suction on the aerodynamic performance of bowed compressor cascades is discussed in this paper. Preliminary studies are conducted in the context of a highly loaded compressor cascade with peak diffusion factor of 0.60 and camber angle of 60 degrees. Comparison between numerical simulation results and experiment data shows that blade bowing may well help to modify the radial migration of flow features and prevent the blade suction surface boundary layer from separating. It is noteworthy that there exists an optimum blade bowing design with different operating conditions to increase the incidence range and reduce the loss over the incidence range. With the introduction of the boundary layer suction, the blade design becomes more complicated. This paper, therefore, conducts a thorough numerical study on design parameters including bowed blade geometry, aspirated flow fraction, and aspiration slot location based on mechanical simplicity and fabrication constraints. For a better understanding of the flow physics, the aspiration slot and plenum are included as part of the computational domain. The aspirated fluid passes into the plenum and is removed through both the hub and the shroud of the blade. From there it can be dumped overboard or carried to another point in the engine to be used as cooling air. Without considering the stagnation pressure loss of the aspirated flow, the blade lose can be sustainably decreased with the growing aspirated flow fractions from 0.5% to 2.5% of the inlet mass flow. However, when the aspirated flow’s effect on stagnation pressure loss is properly quantified, the blade’s loss decreasing trend will be relatively stable or even reversed with the aspirated flow fraction increasing. The calculations show that the application of aspiration on the flow path needs to be investigated and combined with blade bowing to partly counter the negative impacts with the application of aspiration. The application of blade bowing on aspirated blade makes it possible to achieve the same loss reduction by using lower amounts of aspirated flow. In other words, the increase in spanwise pressure gradient near the endwalls can be further utilized to reduce the effects of secondary flow by bowed blade with the same aspirated flow fraction. Aspiration should not be isolated from blade bowing, the optimum blade bowing angle is different on the basis of different aspirated flow fraction and aspiration slot location. The aspiration slot location is determined by the flow phenomena such as the three-dimensional separation in the cascade corner. In consideration of the stagnation pressure loss from the aspirated flow, aspiration inside of the three-dimensional separation region has a beneficial impact on the blade loss. Conversely, it will quickly lose its effectiveness, or even lead to slight deterioration of the aerodynamic performance if aspiration location is in the midspan, outside the three-dimensional separation region.

Performance Investigation Into Supersonic Diffuser for a High Pressure Centrifugal Compressor

2014 ◽  
Author(s):  
Takao Sugimoto ◽  
Tsukinami Kawanishi ◽  
Hiroshige Kumamaru ◽  
Yasumasa Tohbe
Keyword(s):  
High Pressure ◽  
Unsteady Flow ◽  
Performance Test ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Performance Measurements ◽  
High Pressure Compressor ◽  
3D Unsteady Flow ◽  
Supersonic Diffuser ◽  
Industrial Gas Turbine

In high pressure centrifugal compressors, the overall stage performance is greatly influenced by its diffuser performance. Extremely complicated non-uniform and unsteady flow exists in the region between the impeller exit and the diffuser inlet. Furthermore, in the case of supersonic diffuser, shock waves can be observed near the diffuser inlet. These can cause aerodynamic losses. Therefore, it is essential to recognize such complicated flow to realize an appropriate diffuser design. An investigation into the performance of supersonic diffuser was carried out using a high pressure compressor test rig for a small industrial gas turbine with a high back swept impeller and a quasi pipe-shaped channel diffuser. In addition, 3D quasi-unsteady flow analyses of the entire compressor by a RANS code with Non Linear Harmonic method at several operating conditions between surge and choke were conducted to investigate the details of unsteady flow between the impeller exit and the diffuser exit. The results of the performance test and that of the 3D unsteady flow analyses have shown good agreement in the pressure rise and the isentropic efficiency at several operating conditions. These support high accuracy of the flow analyses and the performance measurements.

Review on the aerodynamics of intermediate compressor duct

2020 ◽  
Vol 14 (4) ◽  
pp. 7446-7468
Author(s):  
Manish Sharma ◽  
Beena D. Baloni
Keyword(s):  
High Pressure ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Outer Wall ◽  
Optimization Techniques ◽  
Optimum Pressure ◽  
Research Areas ◽  
Static Pressure Distribution ◽  
High Pressure Compressor ◽  
Pressure Compressor

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length.  This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.

Experimental and numerical analysis to identify the performance limiting mechanisms in solid-state lithium cells under pulse operating conditions

2019 ◽  
Vol 21 (41) ◽  
pp. 22740-22755 ◽  
Author(s):  
Mei-Chin Pang ◽  
Yucang Hao ◽  
Monica Marinescu ◽  
Huizhi Wang ◽  
Mu Chen ◽  
...  
Keyword(s):  
Solid State ◽  
Numerical Analysis ◽  
Energy Density ◽  
Lithium Ion Batteries ◽  
Lithium Batteries ◽  
Safety Concern ◽  
Lithium Ion ◽  
Thermal Runaway ◽  
Operating Conditions ◽  
Lithium Cells

Solid-state lithium batteries could reduce the safety concern due to thermal runaway while improving the gravimetric and volumetric energy density beyond the existing practical limits of lithium-ion batteries.

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