Heat Transfer Performance of Internal Cooling Turbine Blades Using Cutted-Root Rib Design

2020 ◽  
Author(s):  
Cong-Truong Dinh ◽  
Tai-Duy Vu ◽  
Tan-Hung Dinh ◽  
Phi-Minh Nguyen
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Heat Transfer Performance ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Transfer Performance ◽  
External Cooling

Abstract In gas turbines, the turbine blades are always working in the highly temperature overhead the permissible metal temperatures. To safe operation, the turbine blades are needed to cool. Many researchs in turbine cooling technology can be categorized as internal and external cooling. This paper presents an investigation of cutted-root rib design, where a part of rib was truncated below to create an extra-passage in the root rib applied in the internal cooling turbine blades of jet engine using three-dimensional Reynolds-averaged Navier-Stokes with the SST model. The object of this investigation is to reduce the vortex occurring near the rib for improving the performance of heat transfer, such as the Nusselt number and thermal performance factor. To investigate the heat transfer performance and fluid flow characteristics of internal cooling turbine blades, a parametric study of the cutted-root rib was performed using various geometric parameters related to the height and shapes of the extra-passage. The cutted-root rib geometry is designed in ANSYS DesignModeler, and then meshed by using ICEM-CFD, analysed and post-processed using Ansys-CFX. The numerical results showed that all heat transfer parameter with the cutted-root rib design was greater than the original case without cutted-root rib.

Flow Characteristics in a Three-Dimensional Rectangular Channel With a Pair of Ribs Placed Symmetrically at the Channel Walls

2000 ◽  
Author(s):  
M. Singh ◽  
P. K. Panigrahi ◽  
G. Biswas
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Complex Flow ◽  
Energy Equations

Abstract A numerical study of rib augmented cooling of turbine blades is reported in this paper. The time-dependent velocity field around a pair of symmetrically placed ribs on the walls of a three-dimensional rectangular channel was studied by use of a modified version of Marker-And-Cell algorithm to solve the unsteady incompressible Navier-Stokes and energy equations. The flow structures are presented with the help of instantaneous velocity vector and vorticity fields, FFT and time averaged and rms values of components of velocity. The spanwise averaged Nusselt number is found to increase at the locations of reattachment. The numerical results are compared with available numerical and experimental results. The presence of ribs leads to complex flow fields with regions of flow separation before and after the ribs. Each interruption in the flow field due to the surface mounted rib enables the velocity distribution to be more homogeneous and a new boundary layer starts developing downstream of the rib. The heat transfer is primarily enhanced due to the decrease in the thermal resistance owing to the thinner boundary layers on the interrupted surfaces. Another reason for heat transfer enhancement can be attributed to the mixing induced by large-scale structures present downstream of the separation point.

Flow and Heat Transfer of Mist/Steam Two-Phase Flow in Two-Pass Rectangular Channels With Paralleled and V-Shaped Rib Turbulators

2018 ◽  
Author(s):  
Guangwen Jiang ◽  
Jianmin Gao ◽  
Xiaojun Shi ◽  
Wang Zhao ◽  
Yunlong Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Internal Cooling ◽  
Phase Flow ◽  
Transfer Performance ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Cooling Passage

The heat and flow characteristics of mist/steam two-phase flow in U-shaped internal cooling passage of gas turbine blade are studid numerically in this paper. The standard k-ε model was used as the turbulence model combined with the DPM model to calculate the influence of mist/steam mass ratio and mist diameter on flow and heat transfer of U-passage with different shaped ribs. The result indicates that under the same working condition, the U-shaped channel with 45 deg. V-shaped ribs has better heat transfer performance than other channels and heat transfer non-uniformity of the U-shaped channel with 75 deg. ribs is the worst among all channels studied in this paper. The heat transfer performance of the U-shaped channel with V-shaped ribs is higher than that of the channel with paralleled ribs. As for the mist/steam cooling in U-shaped passage with same ribs structure, heat transfer non-uniformity increases with the increasing of heat transfer performance. When mists diameter increases from 5μm to 15μm, the heat transfer performance of the Second-Flow-Passage increases obviously and the heat transfer non-uniformity increases at the same time. The heat transfer performance has not been further enhanced when the mists diameter continuously increases after mist diameter are larger than 10μm.

Numerical investigation of truncated-root rib on heat transfer performance of internal cooling turbine blades

2021 ◽  
Vol 33 (7) ◽  
pp. 076104
Author(s):  
C. T. Dinh ◽  
T. M. Nguyen ◽  
T. D. Vu ◽  
S. G. Park ◽  
Q. H. Nguyen
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Heat Transfer Performance ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Transfer Performance

Heat Transfer Performance of a New Fan-Shaped Pin-Fin in Internal Cooling Channel

2013 ◽  
Author(s):  
Mi-Ae Moon ◽  
Kwang-Yong Kim
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Performance ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Transfer Performance ◽  
Pin Fin ◽  
Sst Model ◽  
Rear Part ◽  
Rans Analysis

Prediction of convective heat transfer around a pin-fin of novel fan-shape has been performed with Reynolds-averaged Navier-Stokes (RANS) analysis in comparison with a circular pin-fin. The low-Reynolds number shear stress transport (SST) model has been selected as the turbulence closure model by comparing the performance with those of the standard k-ε and k-ω models. The fan-shaped pin-fin has shown remarkably improved heat transfer performance compared to the circular pin-fin over the whole range of Reynolds number (Re = 5,000–100,000). A parametric study with two geometric parameters of the fan-shaped pin-fin, the lateral reduction angle of the fan-shaped pin-fin and radius of rear part of pin-fin has been performed to find their effects on heat transfer and friction loss.

Effects of Boot-Shaped Rib On Heat Transfer Characteristics of Internal Cooling Turbine Blades

2020 ◽  
Author(s):  
Ky-Quang Pham ◽  
Quang-Hai Nguyen ◽  
Tai-Duy Vu ◽  
Cong-Truong Dinh
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Wall Friction ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Toe Angle

Abstract Gas turbine engine has been widely applied to many heavy industries, such as marine propulsion and aerospace fields. Increasing turbine inlet temperature is one of the major ways to improve the thermal efficiency of gas turbines. Internal cooling for gas turbine cooling system is one of the most commonly used approaches to reduce the temperature of blades by casting various kinds of ribs in serpentine passages to enhance the heat transfer between the coolant and hot surface of gas turbine blades. This paper presents an investigation of boot-shaped rib design to increase the heat transfer performances in the internal cooling turbine blades for gas turbine engines. By varying the design parameter configuration, the airflow is taken with higher momentum, and the minor vortex being at the front rib is relatively removed. The object of this investigation is increasing the reattachment airflow to wall and reducing the vortex occurring near the rib for improving the performances of heat transfer using three-dimensional Reynolds-averaged Navier-Stokes with the SST model. A parametric study of the boot-shaped rib design was performed using various geometric parameters related to the heel-angle, toe-angle, slope-height and rib-width to find their effect on the Nusselt number, temperature on the ribbed wall, friction factor ratio of the channel and thermal performance factor. The numerical results showed that the heat transfer performances are significantly increased with the heel-angle, toe-angle, slope-height, while that remained relatively constant with the rib-width.

Investigating Gas Turbine Internal Cooling Using Supercritical CO2 at High Reynolds Numbers for Direct Fired Cycle Applications

2021 ◽  
Author(s):  
Matthew Searle ◽  
Arnab Roy ◽  
James Black ◽  
Doug Straub ◽  
Sridharan Ramesh
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Gas Turbines ◽  
Cfd Simulation ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Process Conditions ◽  
Internal Cooling ◽  
Air Breathing

Abstract In this paper, experimental and numerical investigations of three variants of internal cooling configurations — dimples only, ribs only and ribs with dimples have been explored at process conditions (96°C and 207bar) with sCO2 as the coolant. The designs were chosen based on a review of advanced internal cooling features typically used for air-breathing gas turbines. The experimental study described in this paper utilizes additively manufactured square channels with the cooling features over a range of Reynolds number from 80,000 to 250,000. Nusselt number is calculated in the experiments utilizing the Wilson Plot method and three heat transfer characteristics — augmentation in Nusselt number, friction factor and overall Thermal Performance Factor (TPF) are reported. To explore the effect of surface roughness introduced due to additive manufacturing, two baseline channel flow cases are considered — a conventional smooth tube and an additively manufactured square tube. A companion computational fluid dynamics (CFD) simulation is also performed for the corresponding cooling configurations reported in the experiments using the Reynolds Averaged Navier Stokes (RANS) based turbulence model. Both experimental and computational results show increasing Nusselt number augmentation as higher Reynolds numbers are approached, whereas prior work on internal cooling of air-breathing gas turbines predict a decay in the heat transfer enhancement as Reynolds number increases. Comparing cooling features, it is observed that the “ribs only” and “ribs with dimples” configurations exhibit higher Nusselt number augmentation at all Reynolds numbers compared to the “dimples only” and the “no features” configurations. However, the frictional losses are almost an order of magnitude higher in presence of ribs.

scholarly journals Enhanced heat transfer characteristics of conjugated air jet impingement on a finned heat sink

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 279-288 ◽  
Author(s):  
Shuxia Qiu ◽  
Peng Xu ◽  
Liping Geng ◽  
Arun Mujumdar ◽  
Zhouting Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Cooling System ◽  
Flow Characteristics ◽  
Jet Impingement ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Air Jet

Air jet impingement is one of the effective cooling techniques employed in micro-electronic industry. To enhance the heat transfer performance, a cooling system with air jet impingement on a finned heat sink is evaluated via the computational fluid dynamics method. A two-dimensional confined slot air impinging on a finned flat plate is modeled. The numerical model is validated by comparison of the computed Nusselt number distribution on the impingement target with published experimental results. The flow characteristics and heat transfer performance of jet impingement on both of smooth and finned heat sinks are compared. It is observed that jet impingement over finned target plate improves the cooling performance significantly. A dimensionless heat transfer enhancement factor is introduced to quantify the effect of jet flow Reynolds number on the finned surface. The effect of rectangular fin dimensions on impingement heat transfer rate is discussed in order to optimize the cooling system. Also, the computed flow and thermal fields of the air impingement system are examined to explore the physical mechanisms for heat transfer enhancement.

scholarly journals Calculation of Convective Heat Transfer in Square-Sectioned Gas Turbine Blade Cooling Channels

1998 ◽  
Author(s):  
Arash Saidi ◽  
Bengt Sundén
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Cross Sections ◽  
Turbine Blades ◽  
Solution Procedure ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Turbine Blade Cooling ◽  
Cooling Channels ◽  
Energy Equations

Internal cooling channels are commonly used to reduce the thermal loads on the gas turbine blades to improve overall efficiency. In this study a numerical investigation has been carried out to provide a validated and consistent method to deal with the prediction of the fluid flow and the heat transfer of such channels with square cross sections. The rotation modified Navier-Stokes and energy equations together with a low-Re number version of the k-ε turbulence model are solved with appropriate boundary conditions. The solution procedure is based on a numerical method using a collocated grid, and the pressure-velocity coupling is handled by the SIMPLEC algorithm. The computations are performed with the assumption of fully developed periodic conditions. The calculations are carried out for smooth ducts with and without rotation and effects of rotation on the heat transfer are described. Similar numerical calculations have carried out for channels with rib-roughened walls. The obtained results are compared with available experimental data and empirical correlations for the heat transfer rate and the friction factor. Some details of the flow and heat transfer fields are also presented.

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