Experimental heat transfer and flow simulations of rectangular channel with twisted-tape pin-fin array

2021 ◽  
Vol 166 ◽  
pp. 120809
Author(s):  
S.W. Chang ◽  
P.-S. Wu ◽  
W.L. Cai ◽  
C.H. Yu
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Twisted Tape ◽  
Flow Simulations ◽  
Pin Fin ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Pin Fin Array

Influences of the Non-Uniform Pin-Fin Array on Heat Transfer Distribution in a Rotating Rectangular Channel

2018 ◽  
Author(s):  
Shuo-Cheng Hung ◽  
Szu-Chi Huang ◽  
Yao-Hsien Liu
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Stationary Case ◽  
Pin Fin ◽  
Liquid Crystal Thermography ◽  
Staggered Arrangement ◽  
Channel Orientation ◽  
Pin Fin Array ◽  
Pin Fin Arrays

The liquid crystal thermography was used to investigate the heat transfer of non-uniform pin-fin arrays in a rotating rectangular channel (AR = 4:1) at a channel orientation of 135°. The pin-fin array consisted of four and three pins in a staggered arrangement. The different sized pins were inserted at the rows exhibiting four pins, which produced a non-uniform distribution of the pin-fin array. The experiments were operated at Reynolds numbers of 10,000 and 20,000 for both stationary and rotating conditions. The rotation number varied from 0 to 0.33 and the buoyancy parameter ranged from 0 to 0.27. Results indicated that various heat transfer contours were observed as a result of flow separation and vortices caused by non-uniform pins. Compared to the stationary case, rotation increased heat transfer on both trailing and leading surfaces. The pin-fin array consisted of 6 and 9 mm pins produced the highest heat transfer and frictional losses under rotation condition.

The Effects of Different Pin-Fin Arrays on Heat Transfer and Pressure Loss in a Narrow Channel

2015 ◽  
Author(s):  
Sin Chien Siw ◽  
Austen D. Fradeneck ◽  
Minking K. Chyu ◽  
Mary Anne Alvin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Loss ◽  
Rectangular Channel ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Hybrid Technique ◽  
Pin Fin ◽  
Smooth Channel ◽  
Pin Fin Array

This paper describes a detailed experimental investigation of a narrow rectangular channel based on the double-wall cooling concept that can be applicable to a gas turbine airfoil. The channel has dimensions of 63.5 mm by 12.7 mm, corresponding to an aspect ratio of 5:1. The pin diameter, D, is 12.7 mm, and the ratio of pin-height-to-diameter, H/D is 1. The inter-pin spacing is varies in both spanwise and streamwise directions to form two inline, and two staggered pin-fin configurations. The Reynolds number, based on the hydraulic diameter of the pin fin and the mean bulk velocity, ranges from 6,000 to 15,000. The experiments employ a hybrid technique based on transient liquid crystal imaging to obtain the distributions of the local heat transfer coefficient over all of the participating surfaces, including the endwalls and all the pin elements. The heat transfer on both the endwall and pin-fin surfaces revealed similar pattern compared to the typical circular pin-fin array, which were conducted at higher Reynolds number. The total heat transfer enhancement of current pin-fin array is approximately four times higher than that of fully developed smooth channel with low pressure loss, which resulted in much higher thermal performance compared to other pin-fin array as reported in the literature.

Heat Transfer of Rotating Rectangular Channel With Diamond Shaped Pin-Fin Array at High Rotation Numbers

2012 ◽  
Author(s):  
S. W. Chang ◽  
T.-M. Liou ◽  
T.-H. Lee
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Turbine Rotor ◽  
Full Field ◽  
Turbine Rotor Blade ◽  
Pin Fin ◽  
Nusselt Numbers ◽  
Static Channel ◽  
Pin Fin Array ◽  
Transfer Properties

This experimental study measured the detailed Nusselt numbers (Nu) distributions over two opposite leading and trailing walls of a rotating rectangular channel fitted with diamond shaped pin-fin array with radially outward flow for gas turbine rotor blade cooling applications. The combined and isolated effects of Reynolds (Re), rotation (Ro) and buoyancy (Bu) numbers on local and area-averaged Nusselt numbers (Nu and Nu) were examined at the test conditions of 5000≤Re≤15000, 0≤Ro≤0.6 and 0.0007≤Bu≤0.31. The present infrared thermography method enables the generation of full-field Nu scans over the rotating endwalls at the realistic engine Ro conditions as the first attempt to reveal the combined rotating buoyancy and Coriolis force effects on heat transfer properties. The selected heat transfer results demonstrate the Coriolis and rotating-buoyancy effects on the heat transfer performances of this rotating channel. Acting by the combined Coriolis and rotating buoyancy effects on the area-averaged heat transfer properties, the rotating leading and trailing area-averaged Nusselt numbers are modified respectively to 0.82–1.52 and 1–1.89 times of the static channel references. A set of physically consistent empirical Nu correlations was generated to permit the assessments of individual and interdependent Re, Ro and Bu effects on the area-averaged heat transfer properties over leading and trailing endwalls.

Heat Transfer and Pressure Loss Characteristics of a Narrow Internal Cooling Passage at Low Reynolds Number

2014 ◽  
Author(s):  
Sin Chien Siw ◽  
Nicholas Miller ◽  
Minking K. Chyu ◽  
Mary Anne Alvin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Loss ◽  
Rectangular Channel ◽  
Internal Cooling ◽  
Hybrid Technique ◽  
Pin Fin ◽  
Smooth Channel ◽  
Cooling Passage ◽  
Pin Fin Array

This paper describes a detailed experimental investigation of a narrow rectangular channel based on the double-wall cooling concept that can be applicable to a gas turbine airfoil. The channel has dimensions of 63.5 mm by 12.7 mm, corresponding to an aspect ratio of 5:1. A single pin-fin element, arranged in 9 rows is fitted into the channel. The pin diameter, D, is 12.7 mm, and the ratio of pin-height-to-diameter, H/D is 1. The pins are arranged based on the typical inter-pin spacing of 2.5D in both spanwise and streamwise directions. The Reynolds number, based on the hydraulic diameter of the pin fin and the mean bulk velocity, ranges from 6,000 to 15,000. The experiments employ a hybrid technique based on transient liquid crystal imaging to obtain the distributions of the local heat transfer coefficient over all of the participating surfaces, including the endwalls and all the pin elements. Commercially available CFD software, ANSYS CFX, is used to qualitatively correlate the experimental results and to provide detailed insights of the flow field created by the array.The heat transfer on both the endwall and pin-fin surfaces revealed similar pattern compared to the typical circular pin-fin array, which were conducted at higher Reynolds number. The total heat transfer enhancement of current pin-fin array is approximately five times higher than that of fully developed smooth channel with low pressure loss, which resulted in much higher thermal performance compared to other pin-fin array as reported in the literature.

Heat Transfer of a Rotating Rectangular Channel With a Diamond-Shaped Pin-Fin Array at High Rotation Numbers

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
S. W. Chang ◽  
T.-M. Liou ◽  
T.-H. Lee
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Turbine Rotor ◽  
Full Field ◽  
Turbine Rotor Blade ◽  
Pin Fin ◽  
Nusselt Numbers ◽  
Static Channel ◽  
Pin Fin Array ◽  
Transfer Properties

This experimental study measured the detailed Nusselt numbers (Nu) distributions over two opposite leading and trailing walls of a rotating rectangular channel fitted with a diamond-shaped pin-fin array with radially outward flow for gas turbine rotor blade cooling applications. The combined and isolated effects of Reynolds (Re), rotation (Ro), and buoyancy (Bu) numbers on local and area-averaged Nusselt numbers (Nu and Nu¯) were examined at the test conditions of 5000 ≤ Re ≤ 15,000, 0 ≤ Ro ≤ 0.6, and 0.0007 ≤ Bu ≤ 0.31. The present infrared thermography method enables the generation of full-field Nu scans over the rotating end walls at the realistic engine Ro conditions as the first attempt to reveal the combined rotating buoyancy and Coriolis force effects on heat transfer properties. The selected heat transfer results demonstrate the Coriolis and rotating-buoyancy effects on the heat transfer performances of this rotating channel. Acting by the combined Coriolis and rotating buoyancy effects on the area-averaged heat transfer properties, the rotating leading and trailing area-averaged Nusselt numbers are modified, respectively, to 0.82–1.52 and 1–1.89 times the static channel references. A set of physically consistent empirical Nu¯ correlations was generated to permit the assessments of individual and interdependent Re, Ro, and Bu effects on the area-averaged heat transfer properties over leading and trailing end walls.

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