Novel Turbulators to Enhance Turbine Blade Internal Heat Transfer Rates

2015 ◽  
Author(s):  
Venkata Naga Ramakumar Bommisetty ◽  
Sridhar Murari ◽  
Jong S. Liu ◽  
Malak F. Malak
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Turbine Blade ◽  
Thermal Performance ◽  
Thermal Load ◽  
Turbine Blades ◽  
Internal Heat ◽  
Current Paper ◽  
Transfer Rates ◽  
Internal Heat Transfer

Turbine blades are driven by hot gases from the combustor. The heat transfer from the hot gases produces substantial thermal load and can affect the performance of the turbine blades. In previous designs, cavities inside the blades were created to pass the coolant. Such cooling designs helped to increase the thermal performance of the blades by taking away the turbine blades’ heat. The cooling effect was further enhanced by increasing the turbulence in the flow of coolant. To increase the turbulence in the cavities, various turbulator designs were proposed. However, most of the designs have also introduced wake area while increasing the turbulence. This reduces the heat exchange between the coolant and the blade. The current paper discusses new designs of tabulators for turbine blades that increase the heat transfer rates of the cooling surface by increasing the turbulence of the coolant flow while minimizing the wake area.

Blade Trailing Edge Heat Transfer

1980 ◽  
Author(s):  
A. Brown ◽  
B. Mandjikas ◽  
J. M. Mudyiwa
Keyword(s):  
Heat Transfer ◽  
Turbine Blades ◽  
Internal Heat ◽  
Maximum Velocity ◽  
Reynolds Numbers ◽  
Trailing Edge ◽  
Pillar Diameter ◽  
Trailing Edges ◽  
Pillar Arrays ◽  
Internal Heat Transfer

In this article measurements of heat transfer, pressure loss, and friction factor inside simulated trailing edges of turbine blades are presented. The trailing edges considered are vented and the internal heat transfer surfaces are extended by means of staggered arrays of pillars interconnecting the blade pressure and suction surfaces. A number of pillar arrays and trailing edge configurations are considered, namely pillar pitch to diameter ratios nominally of 2, 3, and 4 and trailing edge included angles of 0, 10, 15, and 20 deg. The range of Reynolds numbers covered based on pillar diameter and maximum velocity through a row of pillars is from 104 to 2 × 105.

Heat Transfer in Novel Internally-Finned Heat Exchange Passages

2008 ◽  
Author(s):  
Fuguo Zhou ◽  
Sumanta Acharya
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Flow Direction ◽  
Turbine Blades ◽  
Internal Heat ◽  
High Heat ◽  
Internal Cooling ◽  
Transfer Coefficients ◽  
Performance Factors ◽  
High Heat Transfer

Heat exchange passages usually use internal fins to enhance heat transfer. These fins have ranged from simple ribs or turbulators to complex helical inserts. Applications of interest range from traditional heat exchangers to internal cooling of turbine blades. In the present paper, a novel fin design that combines the benefits of swirl, impingement and high heat transfer surface area is presented. Measurements of the internal heat transfer coefficients are provided using a liquid crystal technique. Pressure drop along the passage are also measured, therefore friction factors and thermal performance factors are presented. The experiments cover Reynolds number from 10,000 to 40,000 based on the hydraulic diameter of the main channel of the test section. Two models are tested, which have fins oriented at 30 degree and 45 degree to the flow direction, respectively. The results demonstrate that these novel designs produce overall heat transfer ratios greater than 3 compared to the smooth passage.

Experimental Study of Internal Heat Transfer Coefficients in a Rectangular, Ribbed Channel Using a Non-Invasive, Non-Destructive, Transient Inverse Method

2008 ◽  
Author(s):  
Peter Heidrich ◽  
Jens von Wolfersdorf ◽  
Martin Schnieder
Keyword(s):  
Heat Transfer ◽  
Measurement Method ◽  
Inverse Method ◽  
Turbine Blades ◽  
Internal Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Non Invasive ◽  
Non Destructive ◽  
Internal Heat Transfer

This paper describes a non-invasive, non-destructive inverse measurement method that allows one to determine heat transfer coefficients in internal passages of real turbine blades experimentally. For this purpose, a test rig with a fast responding heater was designed to fulfill the requirement of a sudden increase in the air temperature within the internal cooling passages. The outer surface temperatures of the specimen were measured using an infrared camera. To suggest the spatial distribution of the internal heat transfer coefficients from the transient characteristics of the outside surface temperature the inverse heat transfer problem was solved. Differing from former studies which made a thin wall assumption, the conduction inside a finite wall was modelled. Based on a one-dimensional forward solution the best fitting optimization method, the Levenberg-Marquardt algorithm, was chosen. This was verified with artificial data including random noise with positive results. Experimental data were measured for a rectangular H/W = 1:4 aspect ratio channel made of stainless steel with parallel 90° and 45° ribs at Reynolds numbers from 25,000 to 80,000. Results of 90° ribs were compared with simultaneously acquired data using the transient liquid crystal technique. Furthermore the influence of Reynolds number on pitch averaged heat transfer results were evaluated for both rib configurations. These results based on infrared data were compared with earlier studies. It is concluded that the presented experimental measurement method using the transient inverse method could be used to quantitatively determine heat transfer coefficients in internal passages of real turbine blades.

Heat Transfer Enhancement for Turbine Blade Internal Cooling

2013 ◽  
Author(s):  
Lesley M. Wright ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Critical Role ◽  
Turbine Blades ◽  
Internal Heat ◽  
Impinging Jets ◽  
Industrial Applications ◽  
Internal Cooling ◽  
Heat Transfer Augmentation

Gas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. The turbine inlet temperatures are far above the permissible metal temperatures. Therefore, there is a need to cool the blades for safe operation. Modern developments in turbine cooling technology play a critical role in increasing the thermal efficiency and power output of advanced gas turbine designs. Turbine blades and vanes are cooled internally and externally. This paper focuses on heat transfer augmentation of turbine blade internal cooling. Internal cooling is typically achieved by passing the cooling air through rib-enhanced serpentine passages inside the blades. Impinging jets, pin fins and dimples are also used for enhancing internal cooling heat transfer. In the past 10 years, there has been considerable progress in turbine blade internal cooling research and this paper is emphasized on reviewing selected publications to reflect recent developments in this area. In particular, this paper focuses on the newly developed design concepts as well as the combination of existing cooling techniques for turbine airfoil internal heat transfer augmentation. Rotation effects on the turbine blade leading-edge, triangular-shaped channel, mid-chord multi-pass channel and trailing-edge, wedge-shaped channel with coolant ejection are also considered.

Experimental Study on Flow Behavior and Heat Transfer Enhancement with Distinct Dimpled Gas Turbine Blade Internal Cooling Channel

2021 ◽  
pp. 1-28
Author(s):  
Farah Nazifa Nourin ◽  
Ryoichi S. Amano
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Performance ◽  
Diameter Ratio ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Transfer Enhancement

Abstract The study presents the investigation on heat transfer distribution along a gas turbine blade internal cooling channel. Six different cases were considered in this study, using the smooth surface channel as a baseline. Three different dimples depth-to-diameter ratios with 0.1, 0.25, and 0.50 were considered. Different combinations of partial spherical and leaf dimples were also studied with the Reynolds numbers of 6,000, 20,000, 30,000, 40,000, and 50,000. In addition to the experimental investigation, the numerical study was conducted using Large Eddy Simulation (LES) to validate the data. It was found that the highest depth-to-diameter ratio showed the highest heat transfer rate. However, there is a penalty for increased pressure drop. The highest pressure drop affects the overall thermal performance of the cooling channel. The results showed that the leaf dimpled surface is the best cooling channel based on the highest Reynolds number's heat transfer enhancement and friction factor. However, at the lowest Reynolds number, partial spherical dimples with a 0.25 depth to diameter ratio showed the highest thermal performance.

A split ring—disc electrode with internal heat transfer facilities

1988 ◽  
Vol 33 (2) ◽  
pp. 265-269
Author(s):  
M. Shirkhanzadeh ◽  
V. Ashworth ◽  
G.E. Thompson
Keyword(s):  
Heat Transfer ◽  
Internal Heat ◽  
Disc Electrode ◽  
Split Ring ◽  
Internal Heat Transfer

The Measurement of Full-Surface Internal Heat Transfer Coefficients for Turbine Airfoils Using a Non-Destructive Thermal Inertia Technique

2002 ◽  
Author(s):  
Nirm V. Nirmalan ◽  
Ronald S. Bunker ◽  
Carl R. Hedlung
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
External Surface ◽  
Internal Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Turbine Airfoils ◽  
Non Destructive ◽  
Internal Heat Transfer

A new method has been developed and demonstrated for the non-destructive, quantitative assessment of internal heat transfer coefficient distributions of cooled metallic turbine airfoils. The technique employs the acquisition of full-surface external surface temperature data in response to a thermal transient induced by internal heating/cooling, in conjunction with knowledge of the part wall thickness and geometry, material properties, and internal fluid temperatures. An imaging Infrared camera system is used to record the complete time history of the external surface temperature response during a transient initiated by the introduction of a convecting fluid through the cooling circuit of the part. The transient data obtained is combined with the cooling fluid network model to provide the boundary conditions for a finite element model representing the complete part geometry. A simple 1D lumped thermal capacitance model for each local wall position is used to provide a first estimate of the internal surface heat transfer coefficient distribution. A 3D inverse transient conduction model of the part is then executed with updated internal heat transfer coefficients until convergence is reached with the experimentally measured external wall temperatures as a function of time. This new technique makes possible the accurate quantification of full-surface internal heat transfer coefficient distributions for prototype and production metallic airfoils in a totally non-destructive and non-intrusive manner. The technique is equally applicable to other material types and other cooled/heated components.

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