Research on the Effects of Dimples and Protrusions on Flow and Heat Transfer in Matrix Cooling Channels in Turbine Blades

2019 ◽  
Author(s):  
Yigang Luan ◽  
Lianfeng Yang ◽  
Yue Yin ◽  
Pietro Zunino
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Heat Transfer Performance ◽  
Turbine Blades ◽  
Inlet Temperature ◽  
Transfer Performance ◽  
Turbine Inlet Temperature ◽  
Turbine Engine ◽  
Cooling Channels ◽  
Flow And Heat Transfer

Abstract Nowadays, gas turbine engines play an indispensable role in modern industry, which have been widely used especially in the aviation, marine and energy fields. The turbine inlet temperature is one of the most important factors that influences the performance of the turbine engine. It’s acknowledged that the higher turbine inlet temperature contributes to the overall gas turbine engine efficiency. Therefore, the internal cooling technology of turbine blades is of vital importance. This paper mainly studies the effects of dimples and protrusions on flow and heat transfer in matrix cooling channels and optimize the performance of the matrix cooling structure by numerical simulation and experiment methods. Thirteen cases have been calculated under Re = 10,000∼80,000 by the commercial code ANSYS Fluent. Structures with different layouts of dimples and protrusions were considered, such as the number, distance and the depth ratio. The original model has been strengthened due to the dimple and protrusion structure, which improves heat transfer performance as well as the thermal performance factor (TPF) on condition that the pressure loss increases slightly. Meanwhile, the optimized structures have been made and tested by the transient liquid crystal technique (TLC). A comparison between the CFD results and the experimental data is made. Note that the heat transfer performance is much better when the ratio of the dimple depth and the dimple diameter is equal to 0.3, compared with the ratio of 0.1 and 0.2. In terms of the cases with two sides dimples, the heat transfer can be enhanced by increasing the number of the dimples. In addition, the heat transfer performance is the best when both of dimples and protrusions are applied. Nu/Nu0 and TPF increase by up to approximately 7% and 5% respectively.

An Evaluation of the Application of Nanofluids in Intercooled Cycle Marine Gas Turbine Intercooler

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Ningbo Zhao ◽  
Xueyou Wen ◽  
Shuying Li
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Gas Turbine ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Inlet Temperature ◽  
Transfer Performance ◽  
Pumping Power ◽  
Flow And Heat Transfer ◽  
Overall Performance

Coolant is one of the important factors affecting the overall performance of the intercooler for the intercooled (IC) cycle marine gas turbine. Conventional coolants, such as water and ethylene glycol, have lower thermal conductivity which can hinder the development of highly effective compact intercooler. Nanofluids that consist of nanoparticles and base fluids have superior properties like extensively higher thermal conductivity and heat transfer performance compared to those of base fluids. This paper focuses on the application of two different water-based nanofluids containing aluminum oxide (Al2O3) and copper (Cu) nanoparticles in IC cycle marine gas turbine intercooler. The effectiveness-number of transfer unit method is used to evaluate the flow and heat transfer performance of intercooler, and the thermophysical properties of nanofluids are obtained from literature. Then, the effects of some important parameters, such as nanoparticle volume concentration, coolant Reynolds number, coolant inlet temperature, and gas side operating parameters on the flow and heat transfer performance of intercooler, are discussed in detail. The results demonstrate that nanofluids have excellent heat transfer performance and need lower pumping power in comparison with base fluids under different gas turbine operating conditions. Under the same heat transfer, Cu–water nanofluids can reduce more pumping power than Al2O3–water nanofluids. It is also concluded that the overall performance of intercooler can be enhanced when increasing the nanoparticle volume concentration and coolant Reynolds number and decreasing the coolant inlet temperature.

An Evaluation of the Application of Nanofluids in Intercooled Cycle Marine Gas Turbine Intercooler

2015 ◽  
Author(s):  
Ningbo Zhao ◽  
Xueyou Wen ◽  
Shuying Li
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Gas Turbine ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Inlet Temperature ◽  
Transfer Performance ◽  
Pumping Power ◽  
Flow And Heat Transfer ◽  
Overall Performance

Coolant is one of the important factors affecting the overall performance of the intercooler for the intercooled cycle marine gas turbine. Conventional coolants such as water and ethylene glycol have lower thermal conductivity which can hinder the development of highly effective compact intercooler. Nanofluids that consist of nanoparticles and base fluids have superior properties like extensively higher thermal conductivity and heat transfer performance compared to those of base fluids. This paper focuses on the application of two different water-based nanofluids containing aluminum oxide (Al2O3) and copper (Cu) nanoparticles in intercooled cycle marine gas turbine intercooler. The effectiveness-number of transfer unit method is used to evaluate the flow and heat transfer performance of intercooler and the thermophysical properties of nanofluids are obtained from literature. Then the effects of some important parameters such as nanoparticle volume concentration, coolant Reynolds number, coolant inlet temperature and gas side operating parameters on the flow and heat transfer performance of intercooler are discussed in detail. The results demonstrate that nanofluids have excellent heat transfer performance and need lower pumping power in comparison with base fluids under different gas turbine operating conditions. Under the same heat transfer, Cu-water nanofluids can reduce more pumping power than Al2O3-water nanofluids. It is also concluded that the overall performance of intercooler can be enhanced when increasing the nanoparticle volume concentration and coolant Reynolds number and decreasing the coolant inlet temperature.

Topology Optimization of Serpentine Channels for Minimization of Pressure Loss and Maximization of Heat Transfer Performance As Applied for Additive Manufacturing

2019 ◽  
Author(s):  
Shinjan Ghosh ◽  
Jayanta S. Kapat
Keyword(s):  
Heat Transfer ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Pressure Drop ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Cooling Channels ◽  
Blade Cooling

Abstract Gas Turbine blade cooling is an important topic of research, as a high turbine inlet temperature (TIT) essentially means an increase in efficiency of gas turbine cycles. Internal cooling channels in gas turbine blades are key to the cooling and prevention of thermal failure of the material. Serpentine channels are a common feature in internal blade cooling. Optimization methods are often employed in the design of blade internal cooling channels to improve heat-transfer and reduce pressure drop. Topology optimization uses a variable porosity approach to manipulate flow geometries by adding or removing material. Such a method has been employed in the current work to modify the geometric configuration of a serpentine channel to improve total heat transferred and reduce the pressure drop. An in-house OpenFOAM solver has been used to create non-traditional geometries from two generic designs. Geometry-1 is a 2-D serpentine passage with an inlet and 4 bleeding holes as outlets for ejection into the trailing edge. Geometry-2 is a 3-D serpentine passage with an aspect ratio of 3:1 and consists of two 180-degree bends. The inlet velocity for both the geometries was used as 20 m/s. The governing equations employ a “Brinkman porosity parameter” to account for the porous cells in the flow domain. Results have shown a change in shape of the channel walls to enhance heat-transfer in the passage. Additive manufacturing can be employed to make such unconventional shapes.

scholarly journals Numerical Calculations on Flow and Heat Transfer in Smooth and Ribbed Two-Pass Square Channels under Rotational Effects

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhongyang Shen ◽  
Yonghui Xie ◽  
Di Zhang ◽  
Gongnan Xie
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Transfer Rate ◽  
Heat Transfer Performance ◽  
Thermal Characteristics ◽  
Transfer Performance ◽  
Operation Condition ◽  
Flow And Heat Transfer ◽  
Rotation Numbers ◽  
First Pass

U-shaped channel, which is also called two-pass channel, commonly exists in gas turbine internal coolant passages. Ribbed walls are frequently adopted in internal passage to enhance the heat transfer. Considering the rotational condition of gas turbine blade on operation, the effect of rotation is also investigated for the coolant channel which is close to real operation condition. Thus, the objective of this study is to discuss the effect of rotation on fluid flow and heat transfer performance of U-shaped channel with ribbed walls under high rotational numbers. Investigated Reynolds number is Re=12500and the rotation numbers areRob=0.4and 0.6. In the results, the spatially heat transfer coefficient distributions are exhibited to discuss the effect of rotation and roughened walls. It is found that ribbed walls enhance the heat transfer rate significantly. Under the rotational condition, theNuin the first pass with outward flow is increased while that in the second pass is decreased. Finally, averageNuratio, friction ratio, and thermal performance are all presented to discuss the thermal characteristics.

Numerical Investigation on Flow and Heat Transfer in Matrix Cooling Channels for Turbine Blades

2016 ◽  
Author(s):  
Yigang Luan ◽  
Shi Bu ◽  
Haiou Sun ◽  
Tao Sun
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Structural Parameters ◽  
Turbine Blades ◽  
Channel Width ◽  
Transfer Performance ◽  
Cooling Channel ◽  
Cooling Channels

Matrix cooling is one kind of internal cooling structures applied to protect turbine blades. This paper investigated the flow field and heat transfer performance in matrix cooling channels experimentally and numerically. A testing section (rib angle of 45-deg, rib thickness of 30mm, rib height of 30mm and sub-channel width of 30mm) made of Plexiglas was build and connected to a wind tunnel sysytem. And Transient Liquid Crystal (TLC) technique was applied to obtain the detailed heat transfer distribution on the primary surface inside the matrix cooling channel. The experiment was performed under different Reynolds numbers varying from 18428 to 28327, based on the channel inlet hydraulic diameter; also the overall pressure drop across the channel was measured. Experimental results were used to calibrate the numerical solution obtained by computational fluid dynamics (CFD) method. During the numerical simulation process, structured grids and k-w turbulence model was employed. And a good agreement is obtained between experimental and CFD results for both pressure drop and heat transfer performance. Channels of various structural parameters (rib angle, rib thickness and sub-channel width) were then studied by numerical simulation, three rib angles (30-deg, 45-deg and 60-deg), three rib thicknesses (1.8mm, 3mm and 5mm) and three sub-channel widths (3mm, 5mm and 9mm) were considered, with the rib height 3mm for all the cases. Numerical results showed that the sidewall turnings made the greatest contribution to heat transfer enhancement but caused very large pressure drop meanwhile. The overall heat transfer and pressure drop increase with rib angle and rib width but decrease with sub-channel width. The thermal performance factor decreases with rib angle and rib width, while it showed a non-monotonic dependency on sub-channel width. Among the three structural parameters, rib angle has the most significant effect on the performance of matrix cooling channel.

Computation of Flow and Heat Transfer of a Blade Internal Cooling Passage With Truncated V-Shaped Ribs on Opposite Walls

2012 ◽  
Author(s):  
Shian Li ◽  
Gongnan Xie ◽  
Weihong Zhang ◽  
Bengt Sundén
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Turbine Engine ◽  
Flow And Heat Transfer ◽  
Cooling Passage ◽  
Internal Cooling Passage

The inlet temperature of gas turbine engine is continuously increased to achieve higher thermal efficiency and power output. To prevent from the temperature exceeding the melting point of the blade material, ribs are commonly used in the mid-section of internal blade to augment the heat transfer from blade wall to the coolant. In this study, turbulent flow and heat transfer of a rectangular cooling passage with continuous or truncated 45-deg V-shaped ribs on opposite walls have been investigated numerically. The inlet Reynolds numbers are ranging from 12,000 to 60,000 and the low-Re k-ε model is selected for the turbulent computations. The complex three-dimensional fluid flow in the internal coolant passages and the corresponding heat transfer over the side-walls and rib-walls are presented and the thermal performances of the ribbed passages are compared as well. It is shown that the passage with truncated V-shaped ribs on opposite walls is very effective in improving the heat transfer performance with a low pressure loss, and thus could be suggested to be applied to gas turbine blade internal cooling.

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