Modeling and Measurements of Heat/Mass Transfer in a Linear Turbine Cascade

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
F. Papa ◽  
U. Madanan ◽  
R. J. Goldstein
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Large Scale ◽  
Turbine Blades ◽  
Transition Model ◽  
Turbine Cascade ◽  
Numerical Predictions ◽  
Naphthalene Sublimation Technique ◽  
Sst Model ◽  
End Wall

Measurements of the mass/heat transfer coefficients on the blade and end wall surfaces of a linear turbine cascade are compared to numerical predictions using the standard shear stress transport (SST) closure and the SST model in combination with the Reθ–γ transition model (SST-TRANS). Experiments were carried out in a wind tunnel test section composed of five large-scale turbine blades, using the naphthalene sublimation technique. Two cases were tested, with exit Reynolds number of 600,000 and inlet turbulence values of 0.2% and 4%, respectively. The main secondary flow features, consisting of the horseshoe vortex system, the passage vortex, and the corner vortices, are identified and their influence on heat/mass transfer is analyzed. Numerical simulations were carried out to match the conditions of the experiments. Results show that large improvements are obtained with the introduction of the Reθ–γ transition model. In particular, excellent agreement with the experiments is found, for the whole spanwise extension of the blade, on the pressure surface. On the suction surface, performance is very good in the highly three-dimensional region close to the end wall, but some weaknesses appear in predicting the location of transition in the two-dimensional region. On the end wall surface, the SST model in combination with the transition model produces satisfactory results, greatly improved compared to the standard SST model.

Heat Transfer Study in a Linear Turbine Cascade Using a Thermal Boundary Layer Measurement Technique

2007 ◽  
Vol 129 (10) ◽  
pp. 1384-1394 ◽  
Author(s):  
S. Han ◽  
R. J. Goldstein
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Turbine Blades ◽  
Local Heat Transfer ◽  
Experimental System ◽  
Local Heat ◽  
Turbine Cascade ◽  
Local Measurements ◽  
End Wall ◽  
Five Axis

An experimental system is designed, constructed, and operated to make local measurements of heat transfer from constant-temperature surfaces in a linear turbine cascade. The system includes a number of embedded heaters and a control system to maintain the turbine blades and end walls in the cascade at a uniform temperature. A five-axis measurement system is used to determine temperature profiles normal to the pressure and suction sides of the blades and to the end wall. Extrapolating these measurements close to the surface, the local heat transfer is calculated using Fourier’s law. The system has been tested in the laboratory, and results are shown for the temperature distributions above the surfaces and for the local variations in the Nusselt number on the different surfaces in the cascade. The system can also be used to study the heat and mass transfer analogy as considerable data are available for mass transfer results with similar geometries.

Effect of Wake-Disturbed Flow on Heat (Mass) Transfer to a Turbine Blade

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
S. Olson ◽  
S. Sanitjai ◽  
K. Ghosh ◽  
R. J. Goldstein
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Turbine Blade ◽  
Heat Mass Transfer ◽  
Turbine Blades ◽  
Freestream Turbulence ◽  
Suction Surface ◽  
Disturbed Flow ◽  
Linear Cascade ◽  
Naphthalene Sublimation Technique

This study investigates the effect of wakes in the presence of varying levels of background freestream turbulence on the heat (mass) transfer from gas turbine blades. Measurements using the naphthalene sublimation technique provide local values of the mass transfer coefficient on the pressure and suction surfaces of a simulated turbine blade in a linear cascade. Experimental parameters studied include the pitch of the wake-generating blades (vanes), blade-row separation, Reynolds number, and the freestream turbulence level. The disturbed flow strongly affects the mass transfer Stanton number on both sides of the blade, particularly along the suction surface. An earlier transition to a turbulent boundary layer occurs with increased background turbulence, higher Reynolds number, and from wakes shed from vanes placed upstream of the linear cascade. Note that once the effects on mass transfer are known, similar variation on heat transfer can be inferred from the heat/mass transfer analogy.

Influence of Blade Leading Edge Geometry on Turbine Endwall Heat(Mass) Transfer

2005 ◽  
Author(s):  
S. Han ◽  
R. J. Goldstein
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Leading Edge ◽  
Local Heat ◽  
Secondary Flows ◽  
Transfer Performance ◽  
Turbine Cascade ◽  
Suction Surface ◽  
Naphthalene Sublimation Technique ◽  
Passage Vortex

The secondary flows, including passage and other vortices in a turbine cascade cause significant aerodynamic losses and thermal gradients. Leading-edge modification of the blade has drawn considerable attention as it has been shown to reduce the secondary flows. However, the heat transfer performance of a leading-edge modified blade has not been investigated thoroughly. Since a fillet at the leading edge blade is reported to reduce the aerodynamic loss significantly, the naphthalene sublimation technique with a fillet geometry is used to study local heat (mass) transfer performance in a simulated turbine cascade. The present paper compares Sherwood number distributions on an endwall with a simple blade and a similar blade having modified leading-edge by adding a fillet. With the modified blades, a horseshoe vortex is not observed and the passage vortex is delayed or not observed for different turbulence intensities. However, near the blade trailing edge the passage vortex has gained as much strength as with the simple blade for low turbulence intensity. Near the leading edge on the pressure and the suction surface, higher mass transfer regions are observed with the fillets. Apparently the corner vortices are intensified with the leading-edge modified blade.

Influence of Blade Leading Edge Geometry on Turbine Endwall Heat (Mass) Transfer

2005 ◽  
Vol 128 (4) ◽  
pp. 798-813 ◽  
Author(s):  
S. Han ◽  
R. J. Goldstein
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Leading Edge ◽  
Local Heat ◽  
Secondary Flows ◽  
Transfer Performance ◽  
Turbine Cascade ◽  
Suction Surface ◽  
Naphthalene Sublimation Technique ◽  
Passage Vortex

The secondary flows, including passage and other vortices in a turbine cascade, cause significant aerodynamic losses and thermal gradients. Leading edge modification of the blade has drawn considerable attention as it has been shown to reduce the secondary flows. However, the heat transfer performance of a leading edge modified blade has not been investigated thoroughly. Since a fillet at the leading edge blade is reported to reduce the aerodynamic loss significantly, the naphthalene sublimation technique with a fillet geometry is used to study local heat (mass) transfer performance in a simulated turbine cascade. The present paper compares Sherwood number distributions on an endwall with a simple blade and a similar blade having a modified leading edge by adding a fillet. With the modified blades, a horseshoe vortex is not observed and the passage vortex is delayed or not observed for different turbulence intensities. However, near the blade trailing edge the passage vortex has gained as much strength as with the simple blade for low turbulence intensity. Near the leading edge on the pressure and the suction surface, higher mass transfer regions are observed with the fillets. Apparently the corner vortices are intensified with the leading edge modified blade.

Effect of Wake-Disturbed Flow on Heat (Mass) Transfer to a Turbine Blade

2009 ◽  
Author(s):  
S. J. Olson ◽  
S. Sanitjai ◽  
K. Ghosh ◽  
R. J. Goldstein
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Turbine Blade ◽  
Heat Mass Transfer ◽  
Turbine Blades ◽  
Freestream Turbulence ◽  
Suction Surface ◽  
Disturbed Flow ◽  
Linear Cascade ◽  
Naphthalene Sublimation Technique

This study investigates the effect of wakes in the presence of varying levels of background freestream turbulence on the heat (mass) transfer from gas turbine blades. Measurements using the naphthalene sublimation technique provide local values of the mass transfer coefficient on the pressure and suction surfaces of a simulated turbine blade in a linear cascade. Experimental parameters studied include the pitch of the wake-generating blades (vanes), blade-row separation, Reynolds number and the freestream turbulence level. The disturbed flow strongly affects the mass transfer Stanton number on both sides of the blade, particularly along the suction surface. An earlier transition to a turbulent boundary layer occurs with increased background turbulence, higher Reynolds number and from wakes shed from vanes placed upstream of the linear cascade. Note that once the effects on mass transfer are known, similar variation on heat transfer can be inferred from the heat/mass transfer analogy.

Influence of Injection Type and Feed Arrangement on Flow and Heat Transfer in an Injection Slot

2001 ◽  
Vol 124 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Hyung Hee Cho ◽  
Jin Ki Ham
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Cooling System ◽  
Transfer Coefficients ◽  
Counter Flow ◽  
Flow Paths ◽  
Mass Transfer Coefficients ◽  
Naphthalene Sublimation Technique ◽  
Vertical Injection ◽  
Injection Type

An experimental investigation is conducted to improve a slot film cooling system used for the cooling of a gas turbine combustor liner. The tangential slots are constructed of discrete holes with different injection types which are the parallel, vertical, and combined to the slot lip. The investigation is focused on the coolant supply systems of normal, inline, and counter-flow paths to the mainstream flow direction. A naphthalene sublimation technique has been employed to measure the local heat/mass transfer coefficients in a slot wall with various injection types and coolant feeding directions. A numerical simulation is also conducted to help understand the flow patterns inside the slot for different injection types. The velocity distributions at the exit of slot lip for the parallel and vertical injection types are fairly uniform with mild periodical patterns with respect to the injection hole positions. However, the combined injection type increases the nonuniformity of flow distribution with the period equaling twice that of hole-to-hole pitch due to splitting and merging of the ejected flows. The dimensionless temperature distributions at the slot exits differ little with blowing rates, injection types, and secondary flow conditions. In the results of heat/mass transfer measurements, the best cooling performance inside the slot is obtained with the vertical injection type among the three different injection types due to the effects of jet impingement. The lateral distributions of heat/mass transfer coefficients with the inline and counter-flow paths are more uniform than the normal-flow path. The average heat/mass transfer coefficients with the injection holes are about two to five times higher than that of a smooth two-dimensional slot path.

Heat/Mass Transfer in a 4:1 AR Smooth and Ribbed Coolant Passage With Rotation in 90-Degree and 45-Degree Orientations

2004 ◽  
Author(s):  
S. Acharya ◽  
P. Agarwal ◽  
D. E. Nikitopoulos
Keyword(s):  
Mass Transfer ◽  
Test Section ◽  
Heat Mass Transfer ◽  
Rectangular Channel ◽  
Spanwise Direction ◽  
Degree Relative ◽  
Naphthalene Sublimation Technique ◽  
Rotation Numbers ◽  
Smooth Channel ◽  
Naphthalene Sublimation

The paper presents an experimental study of heat/mass transfer coefficient in 4:1 aspect ratio rectangular channel with smooth or ribbed walls for Reynolds number in the range of 5,000 to 30,000, rotation numbers in the range of 0–0.12 and for two different orientations of the test-section (90-degree and 45-degree relative to the plane of rotation). Such passages are encountered close to the trailing sections of the turbine blade. Inline normal tips (e/Dh = 0.15625 and p/e = 11.2) are used and placed on the leading and the trailing sides. The experiments are conducted in a rotating two-pass coolant channel facility using the naphthalene sublimation technique. It is observed that for the 45-degree orientation of the test-section, all the walls show an increase in the heat transfer with rotation as opposed to the 90-degree orientation where the stabilized wall shows reduction and the destabilized wall shows enhancement. The spanwise mass transfer distributions in the smooth and the ribbed cases are also presented, and show significant variations in the spanwise direction for the smooth channel.

scholarly journals Highly Resolved Distribution of Heat Transfer for Turbine Leading Edge Film Cooling Including Reynolds Number and Blowing Rate Effects

1998 ◽  
Author(s):  
K. Jung ◽  
D. K. Hennecke
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Heat Mass Transfer ◽  
Leading Edge ◽  
Transfer Coefficients ◽  
Complex Flow ◽  
Long Distance ◽  
Naphthalene Sublimation Technique

The effect of leading edge film cooling on heat transfer was experimentally investigated using the naphthalene sublimation technique. The experiments were performed on a symmetrical model of the leading edge suction side region of a high pressure turbine blade with one row of film cooling holes on each side. Two different lateral inclinations of the injection holes were studied: 0° and 45°. In order to build a data base for the validation and improvement of numerical computations, highly resolved distributions of the heat/mass transfer coefficients were measured. Reynolds numbers (based on hole diameter) were varied from 4000 to 8000 and blowing rate from 0.0 to 1.5. For better interpretation, the results were compared with injection-flow visualizations. Increasing the blowing rate causes more interaction between the jets and the mainstream, which creates higher jet turbulence at the exit of the holes resulting in a higher relative heat transfer. This increase remains constant over quite a long distance dependent on the Reynolds number. Increasing the Reynolds number keeps the jets closer to the wall resulting in higher relative heat transfer. The highly resolved heat/mass transfer distribution shows the influence of the complex flow field in the near hole region on the heat transfer values along the surface.

Characterization of Impingement Heat/Mass Transfer to the Synthetic Jet Generated by a Biomimetic Actuator

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Zdeněk Trávníček ◽  
Zuzana Broučková
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Mass Transfer Rate ◽  
Jet Impingement ◽  
Flux Measurement ◽  
Impinging Jets ◽  
Synthetic Jet ◽  
Working Fluid ◽  
Naphthalene Sublimation Technique ◽  
Flexible Diaphragm

Two biomimetic synthetic jet (SJ) actuators were designed, manufactured, and tested under conditions of a jet impingement onto a wall. Nozzles of the actuators were formed by a flexible diaphragm rim, the working fluid was air, and the operating frequencies were chosen near the resonance at 65 Hz and 69 Hz. Four experimental methods were used: phase-locked visualization of the oscillating nozzle lips, jet momentum flux measurement using a precision scale, hot-wire anemometry, and mass transfer measurement using the naphthalene sublimation technique. The results demonstrated possibilities of the proposed actuators to cause a desired heat/mass transfer distribution on the exposed wall. It was concluded that the heat/mass transfer rate was commensurable with a conventional continuous impinging jets (IJs) at the same Reynolds numbers.

Sign in / Sign up

Export Citation Format

Share Document