Effects of novel turning vanes on pressure loss and tip-wall heat transfer in an idealized U-bend channel

2021 ◽  
Vol 121 ◽  
pp. 105072
Author(s):  
Bin Wu ◽  
Xing Yang ◽  
Zhao Liu ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Pressure Loss ◽  
Wall Heat Transfer ◽  
Bend Channel

Flow and Heat Transfer Characteristics in Models of Turbine Blade Tip-Walls With Three Kinds of Turning Vanes

2018 ◽  
Author(s):  
Bin Wu ◽  
Xing Yang ◽  
Lv Ye ◽  
Zhao Liu ◽  
Yu Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Double Layer ◽  
Pressure Loss ◽  
Stokes Equations ◽  
Wall Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Blade Tip

In this paper, effects of three kinds of turning vanes on flow and heat transfer of turbine blade tip-walls with a U-shaped channel have been numerically studied. Numerical simulations are performed to solve three-dimensional, steady, Reynolds-averaged Navier-Stokes equations with the standard k-ω turbulence model. The aspect ratio (AR) and the hydraulic diameter of the channel are 2 and 93.13 mm, respectively. The effects of single-layer, double-layer and double-layer dome-shaped turning vanes in the turn region on the tip-wall heat transfer and overall pressure loss of rectangular U-shaped channels are analyzed. Detailed flow and heat transfer characteristics over the tip-walls, as well as the overall performance, are presented and compared with each other. Results show that the tip-wall heat transfer coefficients with double-layer dome-shaped turning vanes are the highest among the three cases. Double-layer dome-shaped turning vanes can promote the lateral spreading of secondary flow and effectively increase the uniformity of heat transfer on the tip-wall. More importantly, this structure can make the cooling air expand and accelerate at the center region of the top of the U-shaped channel, resulting in more heat to be removed from the tip-wall. Additionally, double-layer dome-shaped turning vanes can effectively reduce the pressure loss of the channel.

Effect of Mesh Topologies on Wall Heat Transfer and Pressure Loss Prediction of a Blade Coolant Passage

2013 ◽  
Vol 315 ◽  
pp. 216-220 ◽  
Author(s):  
Marwan Effendy ◽  
Yu Feng Yao ◽  
Jun Yao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Turbulence Intensity ◽  
Pressure Loss ◽  
Wall Heat Transfer ◽  
Adiabatic Wall ◽  
Pin Fin ◽  
Wall Condition ◽  
Cooling Passage

This paper studies the effect of mesh topologies such as hybrid and structured meshes on the evaluation of wall heat transfer coefficient (HTC) and pressure loss of a blade cooling passage. An experimental model is chosen; it has five-row of stream wise staggered elliptical pin-fin fitted inside a 10owedge-shape duct and one-row of fillet circular pin-fin in the exit region. Simulations consider two types; i.e. warm test with isothermal wall condition and cold test with adiabatic wall condition respectively, in order to evaluate flow and thermal characteristics such as HTC and pressure loss. Further simulations are carried out by varying Re number, wall surfaces roughness, inlet turbulence intensity and turbulence models. It was found that for unstructured or structured mesh with proper near wall and middle passage grid resolutions, CFD predicted HTC and pressure loss are in good agreement with available experimental data. The wall surface roughness is found to have significant impact on HTC, simulations produce results in better agreement with experimental measurements. Simulation results also confirm that inlet turbulence intensity and turbulence model have insignificant effect of predicting the pin-fin wall and end wall heat transfer coefficient.

An Experimental Study of Heat Transfer on a Smooth U-Bend Channel Surface

2012 ◽  
Author(s):  
Lei Wang ◽  
Tareq Salameh ◽  
Bengt Sundén
Keyword(s):  
Heat Transfer ◽  
Experimental Studies ◽  
Jet Impingement ◽  
Wall Heat Transfer ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Primary Mechanism ◽  
Channel Surface ◽  
Bend Channel ◽  
Nozzle Plate

Experimental studies are carried out to investigate the tip-wall heat transfer in a U-bend channel. Liquid crystal technique is employed to measure the wall temperature and obtain the heat transfer coefficients. The Reynolds number is varied from 10,000 to 24,000. It is found that the tip-wall heat transfer in a U-bend channel is characterized by the feature of jet impingement. The local Nusselt number is scaled by a factor of Re0.5, which is close to the heat transfer scaling in the jet impingement for low nozzle-plate spacings. The result corroborates the previous studies that the jet impingement is a primary mechanism to enhance the heat transfer in a U-bend channel.

An Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Rectangular Channel With V-Shaped Ribs

2006 ◽  
Author(s):  
Michael Maurer ◽  
Jens von Wolfersdorf ◽  
Michael Gritsch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Pressure Loss ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
High Reynolds Numbers ◽  
High Reynolds

An experimental and numerical study was conducted to determine the thermal performance of V-shaped ribs in a rectangular channel with an aspect ratio of 2:1. Local heat transfer coefficients were measured using the steady state thermochromic liquid crystal technique. Periodic pressure losses were obtained with pressure taps along the smooth channel sidewall. Reynolds numbers from 95,000 to 500,000 were investigated with V-shaped ribs located on one side or on both sides of the test channel. The rib height-to-hydraulic diameter ratios (e/Dh) were 0.0625 and 0.02, and the rib pitch-to-height ratio (P/e) was 10. In addition, all test cases were investigated numerically. The commercial software FLUENT™ was used with a two-layer k-ε turbulence model. Numerically and experimentally obtained data were compared. It was determined that the heat transfer enhancement based on the heat transfer of a smooth wall levels off for Reynolds numbers over 200,000. The introduction of a second ribbed sidewall slightly increased the heat transfer enhancement whereas the pressure penalty was approximately doubled. Diminishing the rib height at high Reynolds numbers had the disadvantage of a slightly decreased heat transfer enhancement, but benefits in a significantly reduced pressure loss. At high Reynolds numbers small-scale ribs in a one-sided ribbed channel were shown to have the best thermal performance.

Sign in / Sign up

Export Citation Format

Share Document