Flow structure and heat exchange analysis in internal cooling channel of gas turbine blade

2016 ◽  
Vol 25 (4) ◽  
pp. 336-341 ◽  
Author(s):  
Ryszard Szwaba ◽  
Piotr Kaczynski ◽  
Piotr Doerffer ◽  
Janusz Telega
Keyword(s):  
Heat Exchange ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Flow Structure ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Gas Turbine Blade

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.

Detailed Local Heat Transfer Measurements in a Model of a Dendritic Gas Turbine Blade Cooling Design

2011 ◽  
Author(s):  
James Batstone ◽  
David Gillespie ◽  
Eduardo Romero
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Large Scale ◽  
Surface Film ◽  
Internal Heat ◽  
Internal Cooling ◽  
Gas Turbine Blade ◽  
Lift Off ◽  
Number Of Branches

A novel form of gas turbine blade or vane cooling in which passages repeatedly branch within the wall of the cooled component is introduced in this paper. These so called dendritic cooling geometries offer particular performance improvements compared to traditional cooling holes where the external cross flow is low, and conventional films have a tendency to lift off the surface. In these regions improved internal cooling efficiency is achieved, while the coolant film is ejected at a low momentum ratio resulting in reduced aerodynamic losses between the film and hot gases, and a more effective surface film. By varying the number of branches of the systems at a particular location it is possible to tune the flow and heat transfer to the requirements at that location whilst maintaining the pressure margin. The additional loss introduced using the internal branching structure allows a full film-coverage arrangement of holes at the external blade surface. In this paper the results of transient heat transfer experiments characterising the internal heat transfer coefficient distribution in large scale models of dendritic passages are reported. Experiments were conducted with 1, 2 and 3 internal flow branches at a range of engine representative Reynolds numbers and exit momentum ratios. CFD models are used to help explain the flow field in the cooling passages. Furthermore the sensitivity of the pressure loss to the blowing ratio at the exit of the cooling holes is characterised and found to be inversely proportional to the number of branches in the dendritic system. Surprisingly the highly branched systems generally do not exhibit the highest pressure losses.

scholarly journals Cooling Process of Gas Turbine Blade: A Comparison Study

2020 ◽  
Vol 13 (3) ◽  
pp. 215-222
Author(s):  
Akram Luaibi Ballaoot ◽  
Naseer Hamza
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Power Output ◽  
Film Cooling ◽  
Aviation Industry ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Gas Turbine Blade ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet

The gas turbine engines are occupied an important sector in the energy production and aviation industry and this important increase day after day for their features. One of the most important parameters that limit the gas turbine engine power output is the turbine inlet temperature. The higher is the turbine inlet temperature, the higher is the power output or thrust but this increases of risks of blade thermal failure due to metallurgical limits. Thus the need for a good and efficient process of blade cooling can lead to the best compromise between a powerful engine and safe operation. There are two major methods: film or external cooling and internal cooling inside the blade itself. . In the past number of years there has been considerable progress in turbine cooling research and this paper is limited to review a few selected publications to reflect recent development in turbine blade film cooling. The maximum drop in the surface temperature of the gas turbine blade and associated thermal stress – due to incorporating cooling systems- were 735 ˚C, 1217 N/mm2 respectively.

Unsteady RANS Analysis of Particles Deposition in the Coolant Channel of a Gas Turbine Blade Using a Non-Linear Model

2014 ◽  
Author(s):  
Domenico Borello ◽  
Paolo Capobianchi ◽  
Marco De Petris ◽  
Franco Rispoli ◽  
Paolo Venturini
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Solid Particles ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Gas Turbine Blade ◽  
Two Phase ◽  
Cooling Channels ◽  
Non Linear ◽  
Elliptic Relaxation

The two-phase flow in a geometry representing the final portion of the internal cooling channels of a gas turbine blade is here presented and discussed. In the configuration under scrutiny, the coolant flows inside the duct in radial direction and it leaves the blade through the trailing edge after a 90 deg turning. An unsteady Reynolds Averaged Navier-Stokes (URANS) simulation of the flow inside such channel was carried out. An original non-linear version of the well-established ζ-f elliptic relaxation model was developed and applied here. The new model was implemented in the well-validated T-FlowS code currently developed by the authors’ group at Sapienza Università di Roma. The predictions demonstrated a good accuracy of the non-linear URANS model, clearly improving the results of the baseline linear ζ-f model and of the Launder Sharma k-ε model used as reference. The obtained unsteady flow field was adopted to track a large number of solid particles released from several selected sections at the inlet and representing the powders usually dispersed (sand, volcanic ashes) in the air spilled from the compressor and used as cooling fluid. The well-validated particle-tracking algorithm here adopted for determining the trajectories demonstrated to be very sensitive to the flow unsteadiness. Finally, the fouling of the solid surfaces was estimated by adopting a model based on the coefficient of restitution approach.

Study On Flow and Heat Transfer Characteristics of a New-Proposed Alternating Elliptical U-Channel in the Mid-Chord Region of Gas Turbine Blade

2021 ◽  
Author(s):  
Kun Xiao ◽  
Juan He ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Performance ◽  
Cooling Channel ◽  
Gas Turbine Blade ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Bend Channel

Abstract This paper proposed an alternating elliptical U-bend cooling channel which can be applied in the mid-chord region of gas turbine blade and manufactured by precision casting, based on the optimal flow field structure deduced from the Field Synergy Principle, and investigated the flow and heat transfer characteristics in this alternating elliptical U-bend cooling channel thoroughly. Numerical simulations were performed by using 3D steady solver of Reynolds-averaged Navier-Stokes equations (RANS) with the standard k-e turbulence model. The influence of alternating of cross section on heat transfer and pressure drop of the channel was studied by comparing with the smooth elliptical U-bend channel. On this basis, the effect of aspect ratio (length ratio of the major axis to the minor axis) and alternating angle were further investigated. The results showed that, in the first pass of the alternating elliptical U-bend channel, for different Re, four or eight longitudinal vortices were generated. In the second pass, the alternating elliptical channel restrained the flow separation to a certain extent and a double-vortex structure was formed. The average Nusselt number of the alternating elliptical U-bend channel was significantly higher than that of the straight channel, but the pressure loss only increased slightly. With the increase of aspect ratio, the thermal performance of the channel increased, and when the alternating angle is between 40° and 90°, the thermal performance nearly kept constant and also the best.

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