A Trace Gas Technique to Study Mixing in a Turbine Stage

1988 ◽  
Vol 110 (1) ◽  
pp. 38-43 ◽  
Author(s):  
H. D. Joslyn ◽  
R. P. Dring
Keyword(s):  
Temperature Profile ◽  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
Surface Flow ◽  
Trace Gas ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
Radial Temperature ◽  
Gas Concentration

An experimental technique to study mixing in a turbine stage is demonstrated. An axisymmetric, radial temperature profile at the inlet to the first stator of a large-scale, low-speed, single-stage, axial flow turbine model is simulated with a radial trace gas concentration distribution. Mixing or redistribution of the inlet profile by three-dimensional aerodynamic mechanisms (other than temperature-driven mechanisms) is determined from trace gas concentration measurements made in both the stationary and rotating frames of reference at various locations through the turbine. The trace gas concentration contours generated are consistent with flow pitch angle measurements made downstream of the first stator and with surface flow visualization on the rotor airfoil and the hub endwall. It is demonstrated that this trace gas technique is well suited to quantify many aspects of the redistribution and diffusion of an inlet temperature profile as it is convected through a turbine stage.

Three-Dimensional Flow in an Axial Turbine: Part 1 — Aerodynamic Mechanisms

1990 ◽  
Author(s):  
David Joslyn ◽  
Robert Dring
Keyword(s):  
Flow Visualization ◽  
Temperature Profile ◽  
Three Dimensional ◽  
Surface Flow ◽  
Inlet Temperature ◽  
Three Dimensional Flow ◽  
Axial Turbine ◽  
Physical Mechanisms ◽  
Pressure Distributions ◽  
Flow Part

This paper presents an exhaustive experimental documentation of the three–dimensional nature of the flow in a one–and–one–half stage axial turbine. The intent was to examine the flow within, and downstream of, both the stator and rotor airfoil rows so as to delineate the dominant physical mechanisms. Part 1 of this paper presents the aerodynamic results including: (1) airfoil and endwall surface flow visualization, (2) fullspan airfoil pressure distributions, and (3) radial–circumferential distributions of the total and static pressures, and of the yaw and pitch angles in the flow. Part 2 of the paper presents results describing the mixing, or attenuation, of a simulated spanwise inlet temperature profile as it passed through the turbine. Although the flow in each airfoil row possessed a degree of three–dimensionality, that in the rotor was the strongest.

scholarly journals Negative Incidence Flow Over a Turbine Rotor Blade

1983 ◽  
Author(s):  
H. David Joslyn ◽  
Robert P. Dring
Keyword(s):  
Gas Turbines ◽  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
Turbine Rotor ◽  
Surface Flow ◽  
Separated Flows ◽  
Turbine Rotor Blade ◽  
Pressure Surface ◽  
Pressure Distributions

The operation of variable cycle gas turbines at negative incidence can result in highly three dimensional separated flows on the turbine rotor pressure surface. These flows can impact both performance and durability. The present program was conducted to experimentally study the behavior of surface flow on a large scale axial flow turbine rotor with incidence varying up to and including negative incidence separation. Fullspan pressure distributions and surface flow visualization were acquired over a range of incidence. The data indicate that at large negative incidence, pressure surface separation occurred and extended to 60 percent chord at midspan. These separated flows were simulated at midspan by applying potential flow theory to match the measured pressure distributions.

Three-Dimensional Flow in an Axial Turbine: Part 1—Aerodynamic Mechanisms

1992 ◽  
Vol 114 (1) ◽  
pp. 61-70 ◽  
Author(s):  
D. Joslyn ◽  
R. Dring
Keyword(s):  
Flow Visualization ◽  
Temperature Profile ◽  
Three Dimensional ◽  
Surface Flow ◽  
Inlet Temperature ◽  
Three Dimensional Flow ◽  
Axial Turbine ◽  
Physical Mechanisms ◽  
Pressure Distributions ◽  
Flow Part

This paper presents an exhaustive experimental documentation of the three-dimensional nature of the flow in a one-and-one-half stage axial turbine. The intent was to examine the flow within, and downstream of, both the stator and rotor airflow rows so as to delineate the dominant physical mechanisms. Part 1 of this paper presents the aerodynamic results including: (1) airflow and endwall surface flow visualization, (2) full-span airfoil pressure distributions, and (3) radial-circumferential distributions of the total and static pressures, and of the yaw and pitch angles in the flow. Part 2 of the paper presents results describing the mixing, or attenuation, of a simulated spanwise inlet temperature profile as it passed through the turbine. Although the flow in each airfoil row possessed a degree of three-dimensionality, that in the rotor was the strongest.

Effect of Temperature Nonuniformity on Heat Transfer in an Unshrouded Transonic HP Turbine: An Experimental and Computational Investigation

2010 ◽  
Author(s):  
Imran Qureshi ◽  
Andy D. Smith ◽  
Kam S. Chana ◽  
Thomas Povey
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Test Facility ◽  
Effect Of Temperature ◽  
Inlet Temperature ◽  
Experimental Measurements ◽  
Turbine Stage ◽  
Cfd Simulations ◽  
Turbine Inlet

Detailed experimental measurements have been performed to understand the effects of turbine inlet temperature distortion (hot-streaks) on the heat transfer and aerodynamic characteristics of a full-scale unshrouded high pressure turbine stage at flow conditions that are representative of those found in a modern gas turbine engine. To investigate hot-streak migration, the experimental measurements are complemented by three-dimensional steady and unsteady CFD simulations of the turbine stage. This paper presents the time-averaged measurements and computational predictions of rotor blade surface and rotor casing heat transfer. Experimental measurements obtained with and without inlet temperature distortion are compared. Time-mean experimental measurements of rotor casing static pressure are also presented. CFD simulations have been conducted using the Rolls-Royce code Hydra, and are compared to the experimental results. The test turbine was the unshrouded MT1 turbine, installed in the Turbine Test Facility (previously called Isentropic Light Piston Facility) at QinetiQ, Farnborough UK. This is a short duration transonic facility, which simulates engine representative M, Re, Tu, N/T and Tg /Tw at the turbine inlet. The facility has recently been upgraded to incorporate an advanced second-generation temperature distortion generator, capable of simulating well-defined, aggressive temperature distortion both in the radial and circumferential directions, at the turbine inlet.

Effects of Stator Wakes and Spanwise Nonuniform Inlet Conditions on the Rotor Flow of an Axial Turbine Stage

1993 ◽  
Vol 115 (1) ◽  
pp. 128-136 ◽  
Author(s):  
J. Zeschky ◽  
H. E. Gallus
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Tip Clearance ◽  
Hot Wire ◽  
Turbine Stage ◽  
Static Pressure Distribution ◽  
Inlet Conditions ◽  
Experimental Values ◽  
Rotor Flow

Detailed measurements have been performed in a subsonic, axial-flow turbine stage to investigate the structure of the secondary flow field and the loss generation. The data include the static pressure distribution on the rotor blade passage surfaces and radial-circumferential measurements of the rotor exit flow field using three-dimensional hot-wire and pneumatic probes. The flow field at the rotor outlet is derived from unsteady hot-wire measurements with high temporal and spatial resolution. The paper presents the formation of the tip clearance vortex and the passage vortices, which are strongly influenced by the spanwise nonuniform stator outlet flow. Taking the experimental values for the unsteady flow velocities and turbulence properties, the effect of the periodic stator wakes on the rotor flow is discussed.

Experimental Measurements of Ingestion Through Turbine Rim Seals: Part 1—Externally-Induced Ingress

2011 ◽  
Author(s):  
Carl M. Sangan ◽  
Kunyuan Zhou ◽  
J. Michael Owen ◽  
Oliver J. Pountney ◽  
Mike Wilson ◽  
...  
Keyword(s):  
Three Dimensional ◽  
External Pressure ◽  
Operating Conditions ◽  
Turbine Stage ◽  
Research Facility ◽  
Three Dimensional Flow ◽  
Co2 Gas ◽  
Gas Concentration ◽  
Hot Gas ◽  
New Research

This paper describes a new research facility which experimentally models hot gas ingestion into the wheel-space of an axial turbine stage. Measurements of CO2 gas concentration in the rim-seal region and inside the cavity are used to assess the performance of two generic (though engine-representative) rim-seal geometries in terms of the variation of concentration effectiveness with sealing flow rate. The variation of pressure in the turbine annulus, which governs this externally-induced (EI) ingestion, was obtained from steady pressure measurements downstream of the vanes and near the rim seal upstream of the rotating blades. Although the ingestion through the rim seal is a consequence of an unsteady, three-dimensional flow field and the cause-effect relationship between pressure and the sealing effectiveness is complex, the experimental data is shown to be successfully calculated by simple effectiveness equations developed from a previously published orifice model. The data illustrate that, for similar turbine-stage velocity triangles, the effectiveness can be correlated using a non-dimensional sealing parameter, Φo. In principle, and within the limits of dimensional similitude, these correlations should apply to a geometrically-similar engine at the same operating conditions. Part 2 of this paper describes an experimental investigation of rotationally-induced (RI) ingress, where there is no mainsteam flow and consequently no circumferential variation of external pressure.

Effect of Changing Atmospheric and Operating Conditions on the Thermal Stresses in PV Modules

2012 ◽  
Author(s):  
M. U. Siddiqui ◽  
A. F. M. Arif
Keyword(s):  
Power Systems ◽  
Large Scale ◽  
Thermal Stresses ◽  
Direct Method ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Pv Module ◽  
Battery Chargers ◽  
Pv Modules

Photovoltaic (PV) technology provides a direct method to convert solar energy into electricity. In recent years, the use of PV systems has increased greatly with many applications of PV devices in systems as small as battery chargers to large scale electricity generation systems and satellite power systems. An important factor that influences the reliability of photovoltaic modules is their ability to withstand high thermal stresses which develop in PV modules due to the different coefficients of thermal expansion of the different module materials. PV modules also experience thermal cycles which can lead to failure of the module. In the present work, three dimensional numerical thermal and structural models of a PV module were developed and sequentially coupled together to calculate the temperature distribution in the PV module and the thermal stresses developing in it. The model is also capable of simulating PV module cooling. Using the model, a study was conducted to evaluate the thermal and structural performance of the module with and without cooling and the variation in thermal stress magnitudes with changing environmental conditions (solar radiation and ambient temperature) and operating conditions (heat exchanger inlet temperature and velocity).

An Experimental Investigation of the Flow Through an Axial-Flow Pump

1995 ◽  
Vol 117 (3) ◽  
pp. 485-490 ◽  
Author(s):  
W. C. Zierke ◽  
W. A. Straka ◽  
P. D. Taylor
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
Fast Response ◽  
Complex Flow ◽  
Penn State ◽  
Response Pressure ◽  
Axial Flow Pump ◽  
Scale Experiment ◽  
High Reynolds

The high Reynolds number pump (HIREP) facility at ARL Penn State has been used to perform a low-speed, large-scale experiment of the incompressible flow of water through a two-blade-row turbomachine. The objectives of this experiment were to provide a database for comparison with three-dimensional, turbulent flow computations, to evaluate engineering models, and to improve our physical understanding of many of the phenomena involved in this complex flow field. This summary paper briefly describes the experimental facility, as well as the experimental techniques—such as flow visualization, static-pressure measurements, laser Doppler velocimetry, and both slow- and fast-response pressure probes. Then, proceeding from the inlet to the exit of the pump, the paper presents highlights of experimental measurements and data analysis, giving examples of measured physical phenomena such as endwall boundary layers, separation regions, wakes, and secondary vortical structures. In conclusion, this paper provides a synopsis of a well-controlled, larger scope experiment that should prove helpful to those who wish to use the database.

Aerodynamic Aspects of Endwall Film-Cooling

1996 ◽  
Author(s):  
S. Friedrichs ◽  
H. P. Hodson ◽  
W. N. Dawes
Keyword(s):  
Secondary Flow ◽  
Film Cooling ◽  
Large Scale ◽  
Static Pressure ◽  
Three Dimensional ◽  
Surface Flow ◽  
Flow Visualisation ◽  
Film Cooling Effectiveness ◽  
Blade Passage ◽  
Endwall Film Cooling

This paper describes an investigation of the aerodynamic aspects of endwall film-cooling, in which the flow field downstream of a large-scale low-speed linear turbine cascade has been measured. The integrated losses and locations of secondary flow features with and without end wait film-cooling have been determined for variations of both the coolant supply pressure and injection location. Together with previous measurements of adiabatic film-cooling effectiveness and surface-flow visualisation, these results reveal the nature of the interactions between the ejected coolant and the flow in the blade passage. Measured hole massflows and a constant static pressure mixing analysis, together with the measured losses, allow the decomposition of the losses into three distinct entropy generation mechanisms: loss generation within the hole, loss generation due to the mixing of the coolant with the mainstream, and change in secondary loss generation in the blade passage. Results show that the loss generation within the coolant holes is substantial and that ejection into regions of low static pressure increases the loss per unit coolant massflow. Ejection upstream of the three-dimensional separation lines on the endwall changes secondary flow and reduces its associated losses. The results show that it is necessary to take the three-dimensional nature of the endwall flow into account in the design of endwall film-cooling configurations.

scholarly journals WAVE-GENERATED FLOWS ON THE WATER SURFACE

2016 ◽  
Vol 42 ◽  
pp. 1660179
Author(s):  
MICHAEL SHATS ◽  
HORST PUNZMANN ◽  
NICOLAS FRANCOIS ◽  
HUA XIA
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Three Dimensional ◽  
Surface Flow ◽  
Theoretical Problem ◽  
Complex Flows ◽  
Localized Source ◽  
New Methods ◽  
Flow Generation ◽  
Surface Jets

Predicting trajectories of fluid parcels on the water surface perturbed by waves is a difficult mathematical and theoretical problem. It is even harder to model flows generated on the water surface due to complex three-dimensional wave fields, which commonly result from the modulation instability of planar waves. We have recently shown that quasi-standing, or Faraday, waves are capable of generating horizontal fluid motions on the water surface whose statistical properties are very close to those in two-dimensional turbulence. This occurs due to the generation of horizontal vortices. Here we show that progressing waves generated by a localized source are also capable of creating horizontal vortices. The interaction between such vortices can be controlled and used to create stationary surface flows of desired topology. These results offer new methods of surface flow generation, which allow engineering inward and outward surface jets, large-scale vortices and other complex flows. The new principles can be also be used to manipulate floaters on the water surface and to form well-controlled Lagrangian coherent structures on the surface. The resulting flows are localized in a narrow layer near the surface, whose thickness is less than one wavelength.

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