Vehicular Gas Turbine Periodic-Flow Heat Exchanger Solid and Fluid Temperature Distributions

1963 ◽  
Author(s):  
James R. Mondt
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
General Motors ◽  
Periodic Flow ◽  
Fluid Temperature ◽  
Transfer Coefficients ◽  
Temperature Distributions ◽  
Flow Heat

Design, fabrication and operation experience with periodic-flow heat exchangers used in General Motors regenerative vehicular gas turbines has indicated that analysis techniques available in published reports are too restrictive for accurate performance and thermal-distortion calculations. The design usefulness of previously published anaylses is somewhat limited because fluid and metal-temperature distributions are not part of the calculated results. These distributions are required for primary seal matching and core and structural thermal-stress calculations. A nodal analysis has been accomplished at the General Motors Research Laboratories and a type of finite-difference solution obtained for the periodic-flow heat exchanger. This solution can be used to study the effects of longitudinal thermal conduction, variable heat-transfer coefficients, finite rotation, and provides temperature distributions as functions of time and space for transient as well as “steady state.” This has been checked both with available solutions for more simplified cases and some experimental measured results for periodic-flow heat exchangers designed and built as part of the General Motors vehicular regenerative gas-turbine program. A brief outline of the calculation procedures, program capabilities, and some calculated results are presented. This includes temperature distributions for periodic-flow heat exchanger parameters encountered in the vehicular regenerator application.

Vehicular Gas Turbine Periodic-Flow Heat Exchanger Solid and Fluid Temperature Distributions

1964 ◽  
Vol 86 (2) ◽  
pp. 121-126 ◽  
Author(s):  
J. R. Mondt
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
General Motors ◽  
Periodic Flow ◽  
Fluid Temperature ◽  
Transfer Coefficients ◽  
Temperature Distributions ◽  
Flow Heat

Design, fabrication, and operation experience with periodic-flow heat exchangers used in General Motors regenerative vehicular gas turbines has indicated that analysis techniques available in published reports are too restrictive for accurate performance and thermal distortion calculations. The design usefulness of previously published analyses is somewhat limited because fluid and metal temperature distributions are not part of the calculated results. These distributions are required for primary seal matching and core and structural thermal stress calculations. A nodal analysis has been accomplished at the General Motors Research Laboratories and a type of finite difference solution obtained for the periodic-flow heat exchanger. This solution can be used to study the effects of longitudinal thermal conduction, variable heat-transfer coefficients, finite rotation, and provides temperature distributions as functions of time and space for transient as well as “steady-state.” This has been checked both with available solutions for more simplified cases and some experimental measured results for periodic flow heat exchangers designed and built as part of the General Motors vehicular regenerative gas turbine program. A brief outline of the calculation procedures, program capabilities, and some calculated results is presented. This includes temperature distributions for periodic-flow heat-exchanger parameters encountered in the vehicular regenerator application.

The Effect of Longitudinal Heat Conduction on Periodic-Flow Heat Exchanger Performance

1964 ◽  
Vol 86 (2) ◽  
pp. 105-117 ◽  
Author(s):  
G. D. Bahnke ◽  
C. P. Howard
Keyword(s):  
Heat Conduction ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Zero Element ◽  
General Purpose ◽  
Periodic Flow ◽  
Gas Streams ◽  
Flow Heat ◽  
Area Use ◽  
Significant Figures

A numerical finite-difference method of calculating the effectiveness for the periodic-flow type heat exchanger accounting for the effect of longitudinal heat conduction in the direction of fluid flow is presented. The method considers the metal stream in crossflow with each of the gas streams as two separate but dependent heat exchangers. To accommodate the large number of divisions necessary for accuracy and extrapolation to zero element area, use was made of a general purpose digital computer. The values of the effectiveness thus obtained are good to four significant figures while those values for the conduction effect are good to three significant figures. The exchanger effectiveness and conduction effect have been evaluated over the following range of dimensionless parameters. 1.0⩾Cmin/Cmax⩾0.901.0⩽Cr/Cmin⩽∞1.0⩽NTU0⩽1001.0⩾(hA)*⩾0.251.0⩾As*⩾0.250.01⩽λ⩽0.32

Evaluation of Numerical Methods to Predict Temperature Distributions of an Experimentally Investigated Convection-Cooled Gas-Turbine Blade

2017 ◽  
Author(s):  
E. Findeisen ◽  
B. Woerz ◽  
M. Wieler ◽  
P. Jeschke ◽  
M. Rabs
Keyword(s):  
Heat Transfer ◽  
Numerical Methods ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Cooling System ◽  
Fe Model ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Temperature Distributions

This paper presents two different numerical methods to predict the thermal load of a convection-cooled gas-turbine blade under realistic operating temperature conditions. The subject of the investigation is a gas-turbine rotor blade equipped with an academic convection-cooling system and investigated at a cascade test-rig. It consists of three cooling channels, which are connected outside the blade, so allowing cooling air temperature measurements. Both methods use FE models to obtain the temperature distribution of the solid blade. The difference between these methods lies in the generation of the heat transfer coefficients along the cooling channel walls which serve as a boundary condition for the FE model. One method, referred to as the FEM1D method, uses empirical one-dimensional correlations known from the available literature. The other method, the FEM2D method, uses three-dimensional CFD simulations to obtain two-dimensional heat transfer coefficient distributions. The numerical results are compared to each other as well as to experimental data, so that the benefits and limitations of each method can be shown and validated. Overall, this paper provides an evaluation of the different methods which are used to predict temperature distributions in convection-cooled gas-turbines with regard to accuracy, numerical cost and the limitations of each method. The temperature profiles obtained in all methods generally show good agreement with the experiments. However, the more detailed methods produce more accurate results by causing higher numerical costs.

Problems of the Heat Exchanger for Vehicular Gas Turbines

1976 ◽  
Author(s):  
E. Tiefenbacher
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Gas Turbine ◽  
Fuel Consumption ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
Flow Distribution ◽  
Short Review ◽  
Piston Engine

It is well known that a vehicular gas turbine needs a heat exchanger to compete in fuel consumption with the piston engine, especially with the diesel. A short review of the theory of heat exchange shows that very small hydraulic diameters must be used to obtain a reasonable heat exchanger volume. This causes a number of problems for the fabrication, engine configuration, flow distribution, etc. These problems are discussed in conjunction with experience gained during the development of a number of heat exchangers (1).

scholarly journals Evaluation of selected methods of the heat transfer coefficient determination in fin-and-tube cross-flow heat exchangers

2018 ◽  
Vol 240 ◽  
pp. 02004 ◽  
Author(s):  
Tomasz Bury ◽  
Małgorzata Hanuszkiewicz Drapała
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Flow Heat ◽  
The Heat Transfer Coefficient

The work is a part of a thermodynamic analysis of a finned cross-flow heat exchanger of the liquid-gas type. The heat transfer coefficients on the liquid and the gas side and the area of the heat transfer are the main parameters describing such a device. The basic problem in computations of such heat exchangers is determination of the coefficient of the heat transfer from the finned surfaces to the gas. The differences in the heat transfer coefficient local values resulting from the non-uniform flow of mediums through the exchanger complicates the analysis additionally. Six Nusselt number relationships are selected as suitable for the considered heat exchanger, and they are used to calculate the heat transfer coefficient for the air temperature ranging from 10°C to 30°C and for the velocity values ranging from 2 m/s to 20 m/s. In the next step, the gas-side heat transfer coefficient is determined by means of numerical simulations using a numerical model of a repetitive fragment of the heat exchanger under consideration. Finally, the Wilson plot method is also used. The work focuses on an analysis of the in-house HEWES code sensitivity to the method of the heat transfer coefficient determination. The authors believe that the analysis may also be useful for the evaluation of different methods of the heat transfer coefficient computation.

Oscillating Heat Transfer Correlations for Spiral-Coil Thermoacoustic Heat Exchangers

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Kriengkrai Assawamartbunlue ◽  
Channarong Wantha
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Transfer Coefficients ◽  
Spiral Coil ◽  
Heat Transfer Coefficients ◽  
Flow Heat ◽  
Heat Transfer Correlations ◽  
Coil Heat Exchanger ◽  
Coil Heat

Heat exchangers are the important parts in thermoacoustic refrigerators. Types and configurations of the heat exchangers affect flow behaviors through stacks, and heat transfer behaviors between working fluids and the heat exchangers. Steady-flow heat transfer correlations to design a heat exchanger are not suitable for the thermoacoustic refrigerators due to their oscillatory flow conditions in resonator tubes. In this paper, a heat transfer correlation for a spiral-coil heat exchanger is presented. The results from the experimental study were used to develop an empirical equation between the Colburn-j factor, the Prandtl number, and the Reynolds number to correlate the oscillating heat transfer coefficient at the spiral-coil heat exchangers. The results showed that using steady-flow heat transfer correlations for analyses and design of the heat exchanger could result in distinguished errors. The heat transfer correlations developed for oscillatory flows on fin heat exchangers are also not suitable to predict heat transfer coefficients for spiral-coil heat exchanger due to difference in flow behaviors on the heat transfer surface. For oscillatory flows, the heat transfer coefficients can be improved by using curved-liked surface such as spiral coil instead of straightlike surface such as fin coil. The relationships between the oscillating heat transfer coefficients at the heat exchangers, drive ratios, and operating frequencies are also presented. Higher drive ratios and operating frequency result in greater heat transfer coefficients.

The Key Role of Heat Exchangers in Closed Brayton Cycle Gas Turbine Power Plants

1996 ◽  
Author(s):  
Colin F. McDonald
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
Power Plants ◽  
External Source ◽  
Plant Performance ◽  
Brayton Cycle ◽  
Intermediate Heat Exchanger ◽  
Enhance Efficiency

In the power generation field, simple cycle gas turbines are dominant, with heat exchanged variants only selected based on particular user’s requirements. For the lesser known closed Brayton cycle (CBC) power plant, heat exchangers are mandatory. The following three categories of heat exchangers are addressed in this paper, 1) heat input to the closed cycle from an external source; for example the heat exchanger in a fluidized bed combuster in the case of a fossil-fired plant, or an intermediate heat exchanger (IHX) in the case of an indirect cycle nuclear gas turbine, 2) recuperator in the system to enhance efficiency, and 3) exchangers (i.e., precooler and intercooler) for heat rejection from the system. The influence that these heat exchangers have on the selection of system parameters, and plant performance is discussed. Heat exchanger technology state-of-the-art for CBC systems is highlighted.

High Performance Micro-Channel Cross Flow Heat Exchangers

2005 ◽  
Author(s):  
Kevin W. Kelly ◽  
Andrew McCandless ◽  
Christoffe Marques ◽  
Ryan A. Turner ◽  
Shariar Motakef
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
High Performance ◽  
Gas Flow ◽  
Cross Flow ◽  
Micro Channel ◽  
Transfer Coefficients ◽  
Order Of Magnitude ◽  
Flow Heat

The performance of a micro-channel gas-liquid cross flow heat exchanger, manufactured by the LIGA technique is presented. Large heat transfer coefficients are achieved on the gas side by achieving gas-flow passage dimensions as low as 300 microns. Cross flow heat exchanger panels have been produced as large as 20 cm by 15 cm. These panels can be arranged in a variety of ways to produce heat exchangers capable of handling large thermal loads. Experimental results have shown that these heat exchangers are approximately one order of magnitude better, in terms of heat transfer per unit volume, than the commercially available tube-fin heat exchangers with characteristic cross flow channel dimensions that are typically three times larger.

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