Combined 3D Flow and Heat Transfer Measurements in a 2-Pass Internal Coolant Passage of Gas Turbne Airfoils

2002 ◽  
Author(s):  
D. Chanteloup ◽  
Y. Juaneda ◽  
A. Bo¨lcs
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Outer Wall ◽  
Hydraulic Diameter ◽  
Secondary Flows ◽  
Thermochromic Liquid Crystal ◽  
Flow Measurements ◽  
Detailed Measurement ◽  
Flow And Heat Transfer ◽  
Staggered Arrangement

A study of the flow and heat transfer in a stationary model of a two-pass internal coolant passage is presented, which focuses on the flow characteristic effects on the wall heat transfer distribution. Results are given in the upstream fully developed region. Heat transfer measurements were made with a transient technique using thermochromic liquid crystal technique to measure a surface temperature. The technique allows full surface heat transfer coefficient measurements on all the walls. Flow measurements were made with a stereoscopic digital PIV system, which measures all three-velocity components simultaneously. The coolant passage model consists of two square ducts, each having a 20 hydraulic diameter length. The ducts are connected by a sharp 180° bend with a rectangular outer wall. 45° ribs are mounted in a staggered arrangement on the bottom and top walls of both legs. The height of the ribs is equal to 0.1 hydraulic diameters. They are spaced 10 rib heights apart. The flow and heat transfer measurements were obtained at one flow condition with an inlet flow Reynolds number, based on the hydraulic diameter, of 50,000. The paper presents detailed measurement results of the flow characteristics and of the heat transfer distribution in the upstream straight leg of the passage and describes how the main and secondary flows influence the heat transfer distribution in the fully developed regions of the channel.

scholarly journals Combined 3-D Flow and Heat Transfer Measurements in a 2-Pass Internal Coolant Passage of Gas Turbine Airfoils

2002 ◽  
Vol 124 (4) ◽  
pp. 710-718 ◽  
Author(s):  
D. Chanteloup ◽  
Y. Juaneda ◽  
A. Bo¨lcs
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Outer Wall ◽  
Hydraulic Diameter ◽  
Secondary Flows ◽  
Thermochromic Liquid Crystal ◽  
Flow Measurements ◽  
Detailed Measurement ◽  
Flow And Heat Transfer ◽  
Staggered Arrangement

A study of the flow and heat transfer in a stationary model of a two-pass internal coolant passage is presented, which focuses on the flow characteristic effects on the wall heat transfer distribution. Results are given in the upstream fully developed region. Heat transfer measurements were made with a transient technique using thermochromic liquid crystal technique to measure a surface temperature. The technique allows full surface heat transfer coefficient measurements on all the walls. Flow measurements were made with a stereoscopic digital PIV system, which measures all three-velocity components simultaneously. The coolant passage model consists of two square ducts, each having a 20 hydraulic diameter length. The ducts are connected by a sharp 180 deg bend with a rectangular outer wall. 45 deg ribs are mounted in a staggered arrangement on the bottom and top walls of both legs. The height of the ribs is equal to 0.1 hydraulic diameters. They are spaced 10 rib heights apart. The flow and heat transfer measurements were obtained at one flow condition with an inlet flow Reynolds number, based on the hydraulic diameter, of 50,000. The paper presents detailed measurement results of the flow characteristics and of the heat transfer distribution in the upstream straight leg of the passage and describes how the main and secondary flows influence the heat transfer distribution in the fully developed regions of the channel.

Flow Effects on the Bend Region Heat Transfer Distribution of 2-Pass Internal Coolant Passages of Gas Turbine Airfoils: Influence of Film Cooling Extraction

2003 ◽  
Author(s):  
D. Chanteloup ◽  
A. Bo¨lcs
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Hydraulic Diameter ◽  
Secondary Flows ◽  
Full Data ◽  
Data Set ◽  
Flow Measurements ◽  
Detailed Measurement

A study of the flow and heat transfer in stationary models of a two-pass internal coolant passage is presented, which focuses on the flow characteristic effects on the wall heat transfer distribution. Results are given in the sharp 180deg bend region of the channel. The transient thermochromic liquid crystal technique was used. The technique allows full surface heat transfer coefficient measurements on all the walls, in the region of interest. Flow measurements were also conducted with a stereoscopic digital PIV system. The system measures all three-velocity components simultaneously. 3D-streamlines are extracted from the full data set. The coolant passage model consists of two square ducts, each having a 20 hydraulic diameter length. The ducts are connected by a sharp 180deg bend with a rectangular outer wall. 45deg ribs are mounted in a staggered arrangement on the bottom and top walls of both legs. The height of the ribs is equal to 0.1 hydraulic diameters. They are spaced 10 rib heights apart. One geometry is also equipped with extraction holes to simulate holes for film cooling. Two series of holes are placed solely in the bottom wall; four holes are located in the bend, and twelve in the downstream leg. The global extraction through the holes was set to 50% of the inlet massflow. The flow measurements were obtained at one flow condition with an inlet flow Reynolds number, based on the hydraulic diameter, of 50,000. The heat transfer measurements were obtained at the same flow conditions. The paper presents detailed measurement results of the heat transfer distribution on all the channel outer walls in the bend region. It describes how the main and secondary flows govern the heat transfer coefficient in the bend region. It relates the flow recirculating cell structures and the heat transfer distribution on the bend walls. It also shows how the film cooling extraction influences both the recirculating cells and the heat transfer distribution.

scholarly journals Experimental Investigation of Heat Transfer in Two-Pass Coolant Passages With Ribs and Film Cooling Hole Ejection

2002 ◽  
Author(s):  
D. Chanteloup ◽  
A. Bo¨lcs
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Outer Wall ◽  
Reynolds Numbers ◽  
Thermochromic Liquid Crystal ◽  
Heat Transfer Characteristics ◽  
Surface Heat Transfer Coefficient ◽  
Staggered Arrangement ◽  
Cooling Hole ◽  
Surface Measurements

A study of flow in two stationary models of two-pass internal coolant passages is presented, which focuses on the heat transfer characteristics in the two-pass coolant channel. Heat transfer measurements were made with a transient technique using thermochromic liquid crystal technique to measure a surface temperature. The technique allows full surface heat transfer coefficient measurements on all the walls. The coolant passage model consisted of two square passages, each having a 20 hydraulic diameter length, separated by a rounded-tip web of 0.2 passage widths, and connected by a sharp 180 deg bend with a rectangular outer wall. Ribs were mounted on the bottom and top walls of both legs, with a staggered arrangement, and at 45 deg to the flow. The rib height and spacing were 0.1 and 1.0 passage heights, respectively. The measurements were obtained for Reynolds numbers of 25000, 50000 and 70000. One geometry is equipped with extraction holes to simulate holes for film cooling. Two series of holes are placed solely in the bottom wall, 4 holes are located in the bend, and 12 in the downstream leg. The global extraction through the holes was set to 30%, 40% and 50% of the inlet massflow. This paper presents new measurements of the heat transfer in the straight legs, and in the bend of the passage. It shows the influence of Reynolds number and extraction on full surface measurements and area averaged results.

Numerical Simulation of Flow and Heat Transfer Inside a Micro-Channel With One Dimpled Surface

2002 ◽  
Author(s):  
X. J. Wei ◽  
Y. K. Joshi ◽  
P. M. Ligrani
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Secondary Flows ◽  
Bottom Surface ◽  
Micro Channel ◽  
Rectangular Microchannel ◽  
Micro Scale ◽  
Recirculating Flow ◽  
Flow And Heat Transfer ◽  
Macro Scale

Steady, laminar flow and heat transfer, inside a rectangular microchannel with a dimpled bottom surface, are numerically studied using FLUENT 5.5. The microchannel is 50 μm deep and 200 μm wide. The dimples are placed in a single row of along the bottom wall with a pitch of 150 μm. The dimple depth is 20 μm, and the dimple print diameter is 98 μm. Fully developed periodic velocity and temperature boundary conditions are used at the inlet and outlet of one unit cell of the dimpled micro-channel. The numerically predicted, laminar, micro-scale flow characteristics are compared to results from macro-scale studies with turbulent flow. Some of the secondary flows into and out of the dimple, and the recirculating flow within the dimple are similar for both situations. However, the type and number of vortex structures shed from the dimples are significantly different for the laminar-micro-scale flow and turbulent-macro-scale flow. Heat transfer enhancements are present for both situations, but they are somewhat smaller in the laminar-micro-scale flow. In the latter case, these augmentations (relative to a channel with smooth walls) are present both on the bottom-dimpled surface, and on the sidewalls of the channel, and are mostly due to shear layer reattachment, secondary flows produced near the edges of the dimples, and thermal boundary layer thinning. The pressure drop penalties in the laminar-micro-scale flow are either equivalent to, or less than values produced in smooth channels with no dimples.

Experimental Study of Detailed Heat Transfer and Fluid Flow Characteristics in a Rectangular Duct With Solid and Slitted Pentagonal Ribs

2017 ◽  
Author(s):  
Naveen Sharma ◽  
Andallib Tariq ◽  
Manish Mishra
Keyword(s):  
Heat Transfer ◽  
Hot Spot ◽  
Flow Characteristics ◽  
Local Heat Transfer ◽  
Industrial Applications ◽  
Hydraulic Diameter ◽  
Small Scale ◽  
Rectangular Duct ◽  
Reduced Pressure ◽  
Flow Measurements

Rib turbulator is the most effective, economically feasible, and rigorously studied tool to increase thermal performance because of its fundamental nature and due to the vast field of industrial applications. The rib turbulator results in heat transfer enhancement with additional pressure penalties, and thus encourages the researcher and designers towards selecting an efficacious rib configuration. The present work is a study towards detailed heat transfer and flow field characteristics inside a rectangular duct roughened by solid as well as ventilated pentagonal ribs placed transversely on the bottom wall. The rib height-to-hydraulic diameter ratio, the rib pitch-to-height ratio, the open area ratio, and the Reynolds number based on duct hydraulic diameter fixed during experiments are 0.125, 12, 25%, and 42500, respectively. The heat transfer coefficient (HTC) distribution was mapped by using transient Liquid Crystal Thermography (LCT) technique, while detailed flow measurements were made by using Particle Image Velocimetry (PIV) technique. The investigation focuses towards assessing the influence of three different rib configurations named as solid pentagonal ribs, pentagonal rib with parallel slit, and pentagonal rib with inclined slit, on the local heat transfer fields as well as flow characteristics. The flow mechanisms responsible for high or low heat transfer regions as well as for hot-spot formation in the wake of the ribs are identified and explained. The overall heat transfer and friction factor measurements are observed along with the thermohydraulic performance. Results show that the solid pentagonal ribs are superior to slitted ribs from both heat transfer augmentation and thermo-hydraulic performance perspective. Additionally, the slitted pentagonal ribs significantly control the small-scale vortices present at the leeward corner of the solid pentagonal ribs and eventually facilitates in preventing the hot spots formation with reduced pressure penalty.

scholarly journals PIV Investigation of the Flow Characteristics in an Internal Coolant Passage With 45deg Rib Arrangement

1999 ◽  
Author(s):  
J. Schabacker ◽  
A. Boelcs ◽  
B. V. Johnson
Keyword(s):  
Three Dimensional ◽  
Flow Characteristics ◽  
Outer Wall ◽  
Secondary Flows ◽  
Mean Velocity ◽  
Piv Measurements ◽  
Working Medium ◽  
Staggered Arrangement ◽  
Flow Phenomena ◽  
Rib Arrangement

Flow characteristics in a model of a stationary two-pass internal coolant passage were measured with the stereoscopic PIV technique. From the PIV measurements, the 3D mean velocity field and turbulence quantities of the flow were obtained simultaneously with high spatial resolution, which allowed for an understanding of the flow phenomena in the coolant passage. The model of the coolant passage consists of two square legs, each having a length of 19 hydraulic diameters that are connected by a sharp 180deg bend with a rectangular outer wall. In the two legs, 45deg ribs are mounted in a staggered arrangement on the bottom and top wall, with rib heights equal to 0.1 hydraulic diameter, and rib spacing of 10 rib heights. The measurements were carried out for a Reynolds number of 45,700 with air as working medium. The paper presents results of the flow development in the straight legs of the passage and in the bend. The oblique ribs in the straight legs contribute to the development of secondary flows that transport fluid from the leg center towards the walls. In the bend of the passage, the interaction between rib-induced and bend-induced secondary flows leads to a three-dimensional flow. Downstream of the bend, the ribs quickly dominate the flow and thus lead to a fast recovery of the flow from the bend effect.

Analysis of Runback Water Flow on Anti-Icing Surface Using Volume-of-Fluid Method

2017 ◽  
Author(s):  
Mei Zheng ◽  
Wei Dong ◽  
Zhiqiang Guo ◽  
Guilin Lei
Keyword(s):  
Heat Transfer ◽  
Water Flow ◽  
Thin Liquid Film ◽  
Flow Characteristics ◽  
Volume Of Fluid ◽  
Complex Model ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Liquid Film Flow ◽  
The Mathematical Model

The runback water flow and heat transfer on the surface of aircraft components has an important influence on the design of anti-icing system. The aim of this paper is to investigate the water flow characteristics on anti-icing surface using numerical method. The runback water flow on the anti-icing surface, which is caused by the impinging supercooled droplets from the clouds, is driven by the aerodynamic shear forces and the pressure gradient around the components. This is a complex model of flow and heat transfer that considers flow field, super-cooled droplets impingement and runback water flow simultaneously. In this case of gas-liquid two phase flow, the Volume-of-Fluid (VOF) method is very suitable for the solution of thin liquid film flow so that it is applied to simulate the runback water flow on anti-icing surfaces in this paper. Meanwhile, the heat and mass transfer of the runback water flow are considered in the calculation using the User-Defined Functions (UDFs) in ANASYS FLUENT. The verification is conducted by the comparison with the results of the experimental measurement and the mathematical model calculation. The effect of the airflow velocity and contact angle on the water flow are also considered in the numerical simulation.

scholarly journals Investigation of aerodynamics and heat transfer of the modular jet recuperator

2021 ◽  
Vol 2039 (1) ◽  
pp. 012001
Author(s):  
P D Alekseev ◽  
Yu L Leukhin
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Annular Channel ◽  
Secondary Flows ◽  
Cocurrent Flow ◽  
Outlet Section ◽  
Entire Cross Section ◽  
Staggered Arrangement ◽  
Perforated Pipe ◽  
The Impact

Abstract A study of the aerodynamics and heat transfer of a jet modular recuperator with a change in its geometric characteristics has been carried out. The influence of the in-line and staggered arrangement of the blowing holes, as well as the diameter of the perforated pipe is considered. In all considered variants, the number of holes, their diameter and gas flow rate through the recuperator remained unchanged. Numerical modeling of the problem was carried out in a three-dimensional setting using the ANSYS Fluent 15.0 software package. It was found that with the in-line arrangement of the blowing holes, secondary flows are formed between their longitudinal rows in the form of swirling jets of opposite rotation directed towards the outlet section of the recuperative device, through which the main part of the heated air flows out. With the staggered arrangement of the blowing holes, the formation of spiral vortices is disturbed, the air flow is carried out along the entire cross section of the annular channel, increasing the drift effect of the flow on the impact jets, which leads to a decrease in the intensity of heat transfer and its uniformity along the length of the working surface. An increase in the diameter of the inner perforated pipe leads to a decrease in the drift effect of the cocurrent flow on the jets, an increase in the distribution uniformity of the heat flux along the length of the heat transfer surface, and an increase in the heat transfer coefficient.

scholarly journals Heat transfer and flow region characteristics study in a non-annular channel between rotor and stator

2012 ◽  
Vol 16 (2) ◽  
pp. 593-603 ◽  
Author(s):  
M. Nili-Ahmadabadi ◽  
H. Karrabi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flow Characteristics ◽  
Annular Channel ◽  
Flow Region ◽  
Air Gap ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Slip Ring

This paper will present the results of the experimental investigation of heat transfer in a non-annular channel between rotor and stator similar to a real generator. Numerous experiments and numerical studies have examined flow and heat transfer characteristics of a fluid in an annulus with a rotating inner cylinder. In the current study, turbulent flow region and heat transfer characteristics have been studied in the air gap between the rotor and stator of a generator. The test rig has been built in a way which shows a very good agreement with the geometry of a real generator. The boundary condition supplies a non-homogenous heat flux through the passing air channel. The experimental devices and data acquisition method are carefully described in the paper. Surface-mounted thermocouples are located on the both stator and rotor surfaces and one slip ring transfers the collected temperature from rotor to the instrument display. The rotational speed of rotor is fixed at three under: 300rpm, 900 rpm and 1500 rpm. Based on these speeds and hydraulic diameter of the air gap, the Reynolds number has been considered in the range: 4000<Rez<30000. Heat transfer and pressure drop coefficients are deduced from the obtained data based on a theoretical investigation and are expressed as a formula containing effective Reynolds number. To confirm the results, a comparison is presented with Gazley?s (1985) data report. The presented method and established correlations can be applied to other electric machines having similar heat flow characteristics.

Sign in / Sign up

Export Citation Format

Share Document