Temperature Distribution In Blade Research Articles

Cooling channel blockage effect on TBC and substrate behavior in a gas turbine blade failure

In this study, numerical and experimental methods were used to investigate the combined effect of internal cooling channels and thermal barrier coating on temperature distribution and, ultimately, fracture of a real GEF9 turbine blade. The blade comprises TBC layers and internal cooling channels, damaged after 66,000 h of operation. Observations showed blockage of the cooling channels for the fractured blade. The blade temperature distribution was calculated before and after blockage using CFD, and simulation results were used to design the experimental tests. The results show that blockage leads to about a 100-degree increase in blade temperature, 5-µm growth in TGO, and changes in the coating porosity fraction. This causes an increase in ceramic layer stress and the TBC delamination. With the spallation of the TBC layer, the blade is exposed to higher temperatures. Finally, the blade failed due to overheating, accompanied by centrifugal forces related to the blade rotation.

Internal cooling sensitivity analysis to improve the thermal performance of gas turbine blade using a developed robust conjugate heat transfer method

The heat transfer simulations of turbine blades with internal cooling are faced with so many uncertainties, of which some originate from the secondary air system, including the inlet hot gas temperature and pressure and the cooling side boundary conditions, and the blade material. The main objective of this work is to carry out a suitable sensitivity analysis on a specific novel turbine vane to improve the thermal performance of its internal cooling system and to quantify how the uncertainties on the designed/calculated values can desirably/undesirably affect the maximum blade surface temperature, which can consequently affect the gas turbine engine efficiency. Furthermore, the sensitivity analysis is carried out to find the effects of uncertainties of a number of key parameters on the resulting blade temperature distribution. To arrive at trustworthy conclusions, the conjugate heat transfer (CHT) method is used to analyze the heat and fluid flow behavior. This work suitably develops a CHT-based method/solver to perform the proposed study. This method/solver uses a segregated iterative procedure, in which the outer hot gas region is simulated using the computational fluid dynamics (CFD) solver, the flow passing through the connected internal cooling passages is calculated using a 1D correlated-based solver, and the vane conduction is predicted using a 3D finite-element solver, which are fully coupled. The results show that the cooling channel wall temperature has a direct impact on the convective coefficient magnitude; especially in lower temperature regions. As a novel contribution, this work takes into account the cooling wall temperature influence on the 1D code calculations. To implement this, an artificial neural network is suitably trained to predict better convective coefficient. The results of this developed CFD-CHT code are validated against experimental data available for a benchmark vane. Eventually, the sensitivity analysis is carried on the present specific novel turbine vane.

Optimization design and simulationanalysis of composite material anti-/deicing component for wind turbine blade

Wind turbine blades are prone to icing under extreme working conditions, which will reduce the efficiency of wind power generation and seriously affect the service life of wind power system. Therefore, the anti-icing problem of wind turbine blades has become one of the hot topics in wind power technology research. It is of great practical significance to develop anti-icing/deicing technology for wind turbine blades for the safe and effective operation of wind power. In this paper, the numerical simulation optimization design for composite material wind turbine blades anti-/deicing component was studied, and the orthogonal optimization method was employed to optimize the parameters of the wind turbine blade to prevent ice formation. The optimization group parameter group is obtained. Through the wind turbine blade temperature distribution simulation, the correctness of the optimization results of the composite material anti-/deicing component was analyzed. The purpose of this paper is to optimize the heat transfer of anti-/deicing component for composite material wind turbine blade, and lay a theoretical and technical foundation for effectively solving the problem of wind turbine blade icing, which proposing a new composite wind turbine blade anti-/deicing scheme.

Probabilistic CFD computations of gas turbine vane under uncertain operational conditions

The stochastic computations of a NASA gas turbine vane are conducted to investigate the effects of the operational uncertainties on the flow and heat transfer characteristics of the NASA C3X blade. The blade contains ten internal cooling channels to remove heat load. In order to minimize the analysis error the full conjugate heat transfer methodology has been employed to simulate the behavior of external hot gas flows, internal cooling air passages and the solid blade simultaneously. The v2-f turbulence model is used and it is shown the predicted results are in acceptable agreement with the available experimental data. Total pressure, total temperature, turbulence intensity, turbulent length-scale of the inlet and the outlet static pressure are assumed to be stochastic with Beta probability distribution functions. The effects of these uncertainties on flow and thermal fields as well as the blade temperature distribution are studied. The polynomial chaos method with polynomials order p=3 is used to quantify the effects of operational uncertainties. The non-deterministic CFD results are found to be in close agreement with the experimental data. Uncertainties specially in inlet total temperature and turbulent length-scale play key roles on the hydrodynamic and thermal fields around the airfoil also the turbine vane temperature distribution.

A Three-Dimensional Conjugate Approach for Analyzing a Double-Walled Effusion-Cooled Turbine Blade

A double-wall cooling scheme combined with effusion cooling offers a practical approximation to transpiration cooling which in turn presents the potential for very high cooling effectiveness. The use of the conventional conjugate computational fluid dynamics (CFD) for the double-wall blade can be computationally expensive and this approach is therefore less than ideal in cases where only the preliminary results are required. This paper presents a computationally efficient numerical approach for analyzing a double-wall effusion cooled gas turbine blade. An existing correlation from the literature was modified and used to represent the two-dimensional distribution of film cooling effectiveness. The internal heat transfer coefficient was calculated from a validated conjugate analysis of a wall element representing an element of the aerofoil wall and the conduction through the blade solved using a finite element code in ANSYS. The numerical procedure developed has permitted a rapid evaluation of the critical parameters including film cooling effectiveness, blade temperature distribution (and hence metal effectiveness), as well as coolant mass flow consumption. Good agreement was found between the results from this study and that from literature. This paper shows that a straightforward numerical approach that combines an existing correlation for film cooling from the literature with a conjugate analysis of a small wall element can be used to quickly predict the blade temperature distribution and other crucial blade performance parameters.

Comparative study on steady and unsteady conjugate heat transfer analysis of a high pressure turbine blade

In this study, an analysis of steady-state and unsteady-state Conjugate Heat Transfer (CHT) of an aeronautic high pressure gas turbine was conducted, which can calculate fluid and solid domain at the same time. ANSYS CFX V16.0 was used to solve the problem. The main emphasis of this study was on three dimensional behavior of the temperature distribution in blade of the 1st stage high pressure turbine. The Conjugate heat transfer approach in this study is validated with 1983 NASA internally cooled C3X experimental data. Results from the unsteady state were compared to the results of steady state calculations. This paper focuses on the need of unsteady conjugate heat transfer analysis of the rotor blade in cooling design process, with the prediction of the thermal environment around the rotor blade and heat conduction in the rotor blade as it is quite important to carry out the thermal load analysis and life assessment of rotor blades.

Sensitivity Analysis on Turbine Blade Temperature Distribution Using Conjugate Heat Transfer Simulation

Heat transfer parameters are the most critical variables affecting turbine blade life. Therefore, accurately predicting heat transfer parameters is essential. In this study, for precise prediction of the blade temperature distribution, a conjugate heat transfer procedure is used. This procedure involves three different physical aspects: flow and heat transfer in external domain and internal cooling passages and conduction within metal blade. For the external flow simulation and conduction within metal, three-dimensional solvers are used. However, three-dimensional modeling of blade cooling passages is time-consuming because of complex cooling passage geometries. Therefore, in the current work, a one-dimensional network method is used for the simulation of cooling passages. For validation of the numerical procedure, simulation results are compared with the available experimental data for a C3X vane. Results show good agreement against experimental data. The present paper investigates uncertainties of some parameters that affect turbine blade heat transfer, namely, (1) turbine inlet temperature and pressure, (2) upstream stator coolant mass flow rate and temperature, (3) rotor shroud heat transfer coefficient and fluid temperature over shroud, (4) rotor coolant inlet pressure and temperature (as a result of secondary air system), (5) blade metal thermal conductivity, and (6) blade coating thickness and thermal conductivity. Results show that turbine inlet temperature, pressure drop and temperature rise in the secondary air system (SAS) and coating parameters have significant effect on the blade temperature.

Blade cooling improvement for heavy duty gas turbine: the air coolant temperature reduction and the introduction of steam and mixed steam/air cooling

This paper proposes a theoretical study of some alternative solutions to improve the blade cooling in the heavy-duty gas turbine. The study moves to the evaluations of the air coolant reduction temperature effects, considering two different methods: a water surface exchanger (WSE) and a cold water injection (CWI). A logical development of these possible cooling system improvements is the steam cooling application, particularly suitable for mixed or combined gas–steam cycles; the steam cooling is evaluated using open and closed loop configurations; the possible interaction of steam and air cooling is also studied. All the simulation is realized with a family of modular codes developed by authors and the study is conducted with the analysis of the characteristic cooling parameters (efficiency, effectiveness) and by the evaluation of blade temperature distribution. The study is related to a typical configuration of heavy-duty rotor blade with a standard air cooling scheme and the possible variations are related to coolant characteristics only. The results show the interesting possibility due to air coolant temperature reductions, particularly for the CWI method, but the steam cooling turns out to be more incisive. All of the considered techniques show the possibility of a mass coolant reduction and/or the possibility of a maximum cycle temperature increase in comparison to the standard air-cooling. The best results are obtained for an innovative closed–open/steam–air cooling system.