scholarly journals Heat Transfer Analysis in a Single Spool Gas Turbine by Using Calculated-Estimated Coefficients with the Finite Element Method

2020 ◽  
Vol 10 (23) ◽  
pp. 8328
Author(s):  
Geraldo Creci ◽  
Márcio Teixeira de Mendoça ◽  
João Carlos Menezes ◽  
João Roberto Barbosa

In this paper, a calculation procedure is presented to estimate the heat transfer coefficients of a single spool gas turbine designed to generate 5 kN of thrust. These heat transfer coefficients are the boundary conditions which govern the heat interaction between the solid parts and the working fluid in the gas turbine. However, the calculation of these heat transfer coefficients is not a trivial task, since it depends on complex fluid flow conditions. Empirical correlations and assumptions have been used to find convective heat transfer coefficients over most components, including stator vanes, rotor blades, disc faces, and disc platforms. After defining the heat transfer coefficients, the finite element method was used to determine the temperature distribution in one eighth section of the gas turbine making use of the problem cyclic symmetry. Both static and rotating assemblies have been modeled. The results allowed the prediction of the thermal expansion behavior of the whole single spool gas turbine with special attention to the safety margin of clearances. Furthermore, having the temperature distribution defined, it is possible to calculate the thermal stresses in any mechanical component. Additionally, it is possible to specify suitable metallic alloys for achieving appropriate performance in every case. The structural integrity of all components was then assured with the temperature distribution and thermal expansion behavior under knowledge. Thus, the mechanical drawings could be released to manufacturing.

Author(s):  
Hamed Basir ◽  
Ayat Gharehghani ◽  
Abolfazl Ahmadi ◽  
Seyed Mostafa Agha Mirsalim ◽  
Marc A Rosen

Measuring the temperature distribution in a complex and important engine part, such as a turbocharger, is essential for improving engine performance and efficiency. Heat transfer from the turbine to the compressor can strongly influence the turbocharger performance. One of the main measurement methods involves the installation of multiple K-type sensors. However, the location as well as the maximum and minimum temperatures of the turbocharger and the subsequent critical points may not be obtained by using sensors. In the current study, thermocouples, as well as an infra-red camera, are used to study the temperature distribution of the turbocharger housing in a spark ignition engine. A new method is introduced to determine the thermal radiation coefficient of the turbocharger housing by using a laboratory furnace and an infra-red camera. Together with experiments, the finite element method is used to find the temperature distribution in the turbocharger for all thicknesses. Comparing the temperature distribution obtained from simulation with experimental data, an acceptable level of agreement is observed. The location and temperature of the hottest area in experimental and numerical investigations are close to the waste gate. Temperatures using the finite element method for bearings exhibit maximum and minimum errors of 4.9% and 2.3%, respectively, indicating reasonable accuracy for the simulation.


2020 ◽  
Vol 5 ◽  
Author(s):  
Collins O. Akeremale ◽  
Olusegun A Olaiju ◽  
Yeak Su Hoe

In the diagnosis and control of various thermal systems, the philosophy of heat fluxes, and temperatures are very crucial. Temperature as an integral property of any thermal system is understood and also, has well-developed measurement approaches. Though finite difference (FD) had been used to ascertain the distribution of temperature, however, this current article investigates the impact of finite element method (FEM) on temperature distribution in a square plate geometry to compare with finite difference approach. Most times, in industries, cold and hot fluids run through rectangular channels, even in many technical types of equipment. Hence, the distribution of temperature of the plate with different boundary conditions is studied. In this work, let’s develop a finite element method (code) for the solution of a closed squared aluminum plate in a two-dimensional (2D) mixed boundary heat transfer problem at different boundary conditions. To analyze the heat conduction problems, let’s solve the two smooth mixed boundary heat conduction problems using the finite element method and compare the temperature distribution of the plate obtained using the finite difference to that of the plate obtained using the finite element method. The temperature distribution of heat conduction in the 2D heated plate using a finite element method was used to justify the effectiveness of the heat conduction compared with the analytical and finite difference methods


2014 ◽  
Vol 1063 ◽  
pp. 334-338 ◽  
Author(s):  
Tzu Hao Hung ◽  
Heng Kuang Tsai ◽  
Fuh Kuo Chen ◽  
Ping Kun Lee

Due to the complexity of hot stamping mechanism, including the coupling of material formability, thermal interaction and metallurgical microstructure, it makes the process design more difficult even with the aid of the finite element analysis. In the present study, the experimental platforms were developed to measure and derive the friction and heat transfer coefficients, respectively. The experiments at various elevated temperatures and contact pressures were conducted and the friction coefficients and heat transfer coefficients were obtained. A finite element model was also established with the experimental data and the material properties of the boron steel calculated from the JMatPro software. The finite element simulations for the hot stamping forming of an automotive door beam, including transportation analysis, hot forming analysis and die quenching analysis were then performed to examine the forming properties of the door beam. The validation of the finite element results by the production part confirms the efficiency and accuracy of the developed experimental platforms and the finite element analysis for the process design of hot stamping.


2003 ◽  
Vol 125 (4) ◽  
pp. 648-657 ◽  
Author(s):  
Jae Su Kwak ◽  
Je-Chin Han

Experimental investigations were performed to measure the detailed heat transfer coefficients and film cooling effectiveness on the squealer tip of a gas turbine blade in a five-bladed linear cascade. The blade was a two-dimensional model of a first stage gas turbine rotor blade with a profile of the GE-E3 aircraft gas turbine engine rotor blade. The test blade had a squealer (recessed) tip with a 4.22% recess. The blade model was equipped with a single row of film cooling holes on the pressure side near the tip region and the tip surface along the camber line. Hue detection based transient liquid crystals technique was used to measure heat transfer coefficients and film cooling effectiveness. All measurements were done for the three tip gap clearances of 1.0%, 1.5%, and 2.5% of blade span at the two blowing ratios of 1.0 and 2.0. The Reynolds number based on cascade exit velocity and axial chord length was 1.1×106 and the total turning angle of the blade was 97.9 deg. The overall pressure ratio was 1.2 and the inlet and exit Mach numbers were 0.25 and 0.59, respectively. The turbulence intensity level at the cascade inlet was 9.7%. Results showed that the overall heat transfer coefficients increased with increasing tip gap clearance, but decreased with increasing blowing ratio. However, the overall film cooling effectiveness increased with increasing blowing ratio. Results also showed that the overall film cooling effectiveness increased but heat transfer coefficients decreased for the squealer tip when compared to the plane tip at the same tip gap clearance and blowing ratio conditions.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Estaner Claro Romão

This paper proposes an efficient alternative to construction of the linear system coming from a solution via the Finite Element Method that is able to significantly decrease the time of construction of this system. From the presentation of the methodology used and a numerical application it will be clear that the purpose of this work is to be able to decrease 6-7 times (on average) the linear system building time.


Author(s):  
Karthik Krishnaswamy ◽  
◽  
Srikanth Salyan ◽  

The performance of a gas turbine during the service life can be enhanced by cooling the turbine blades efficiently. The objective of this study is to achieve high thermohydraulic performance (THP) inside a cooling passage of a turbine blade having aspect ratio (AR) 1:5 by using discrete W and V-shaped ribs. Hydraulic diameter (Dh) of the cooling passage is 50 mm. Ribs are positioned facing downstream with angle-of-attack (α) of 30° and 45° for discrete W-ribs and discerte V-ribs respectively. The rib profiles with rib height to hydraulic diameter ratio (e/Dh) or blockage ratio 0.06 and pitch (P) 36 mm are tested for Reynolds number (Re) range 30000-75000. Analysis reveals that, area averaged Nusselt numbers of the rib profiles are comparable, with maximum difference of 6% at Re 30000, which is within the limits of uncertainty. Variation of local heat transfer coefficients along the stream exhibited a saw tooth profile, with discrete W-ribs exhibiting higher variations. Along spanwise direction, discrete V-ribs showed larger variations. Maximum variation in local heat transfer coefficients is estimated to be 25%. For experimented Re range, friction loss for discrete W-ribs is higher than discrete-V ribs. Rib profiles exhibited superior heat transfer capabilities. The best Nu/Nuo achieved for discrete Vribs is 3.4 and discrete W-ribs is 3.6. In view of superior heat transfer capabilities, ribs can be deployed in cooling passages near the leading edge, where the temperatures are very high. The best THPo achieved is 3.2 for discrete V-ribs and 3 for discrete W-ribs at Re 30000. The ribs can also enhance the power-toweight ratio as they can produce high thermohydraulic performances for low blockage ratios.


Author(s):  
V T V S Ramachandra Rao ◽  
H Ramasubramanian ◽  
K N Seetharamu

Simulation of the temperature distribution in a brake drum of a commercial truck is carried out using the finite element method. Verification of the predicted values is done using an inertia dynamometer with a data logging system. The effect of variable convective heat-transfer coefficient and the effect of contact area are also studied. From the investigation it is concluded that the present model can be used for the simulation of temperature distribution in rigid brake drums during a fade test.


Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan

The concept of the finite-element procedure may be dated back to 1943 when Courant approximated the warping function linearly in each of an assemblage of triangular elements to the St. Venant torsion problem and proceeded to formulate the problem using the principle of minimum potential energy. Similar ideas were used later by several investigators to obtain the approximate solutions to certain boundary-value problems. It was Clough who first introduced the term “finite elements” in the study of plane elasticity problems. The equivalence of this method with the well-known Ritz method was established at a later date, which made it possible to extend the applications to a broad spectrum of problems for which a variational formulation is possible. Since then numerous studies have been reported on the theory and applications of the finite-element method. In this and next chapters the finite-element formulations necessary for the deformation analysis of metal-forming processes are presented. For hot forming processes, heat transfer analysis should also be carried out as well as deformation analysis. Discretization for temperature calculations and coupling of heat transfer and deformation are discussed in Chap. 12. More detailed descriptions of the method in general and the solution techniques can be found in References [3-5], in addition to the books on the finite-element method listed in Chap. 1. The path to the solution of a problem formulated in finite-element form is described in Chap. 1 (Section 1.2). Discretization of a problem consists of the following steps: (1) describing the element, (2) setting up the element equation, and (3) assembling the element equations. Numerical analysis techniques are then applied for obtaining the solution of the global equations. The basis of the element equations and the assembling into global equations is derived in Chap. 5. The solution satisfying eq. (5.20) is obtained from the admissible velocity fields that are constructed by introducing the shape function in such a way that a continuous velocity field over each element can be denned uniquely in terms of velocities of associated nodal points.


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