Aerothermal Challenges in Syngas, Hydrogen-Fired, and Oxyfuel Turbines—Part I: Gas-Side Heat Transfer

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Minking K. Chyu ◽  
Danny W. Mazzotta ◽  
Sean C. Siw ◽  
Ventzislav G. Karaivanov ◽  
William S. Slaughter ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Gas ◽  
Transfer Coefficient ◽  
Gas Turbines ◽  
Computational Simulation ◽  
Department Of Energy ◽  
Working Fluid ◽  
Computational Fluid Dynamics Analysis ◽  
The Heat Transfer Coefficient

To meet the performance goals of advanced fossil power generation systems, future coal-gas fired turbines will likely be operated at temperatures higher than those in the current commercial natural gas-fired systems. The working fluid in these future turbines could contain substantial moisture (steam), mixed with carbon dioxide, instead of air or nitrogen in conventional gas turbines. As a result, the aerothermal characteristics among the advanced turbine systems are expected to be significantly different, not only from the natural gas turbines but also will be dependent strongly on the compositions of turbine working fluids. Described in this paper is a quantitative comparison of thermal load on the external surface of turbine airfoils that are projected to be utilized in different power cycles the U.S. Department of Energy plans for the next 2 decades. The study is pursued with a computational simulation, based on the three-dimensional computational fluid dynamics analysis. While the heat transfer coefficient has shown to vary strongly along the surface of the airfoil, the projected trends were relatively comparable for airfoils in syngas and hydrogen-fired cycles. However, the heat transfer coefficient for the oxyfuel cycle is found to be substantially higher by about 50–60% than its counterparts in syngas and hydrogen turbines. This is largely caused by the high steam concentration in the turbine flow. Results gained from this study overall suggest that advances in cooling technology and thermal barrier coatings are critical for developments of future coal-based turbine technologies with near zero emissions.

Gas-Side Heat Transfer in Syngas, Hydrogen-Fired and Oxy-Fuel Turbines

2008 ◽  
Author(s):  
Danny W. Mazzotta ◽  
Ventzislav G. Karaivanov ◽  
Minking K. Chyu ◽  
William S. Slaughter ◽  
Mary Anne Alvin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Gas ◽  
Transfer Coefficient ◽  
Gas Turbines ◽  
Fuel Cycle ◽  
Computational Simulation ◽  
Department Of Energy ◽  
Working Fluid ◽  
The Heat Transfer Coefficient

To meet the performance goals of advanced fossil power generation systems; e.g. FutureGen, future coal-gas fired turbines will need to be operated at temperatures higher than those in the current commercial natural gas-fired systems. The working fluid in these future turbines could contain substantial moisture (steam) mixed with carbon dioxide, instead of air or nitrogen in conventional gas turbines. As a result, the aero-thermal characteristics among these new turbines are expected to be significantly different not only from the natural gas turbines but also dependent strongly on the compositions of turbine working fluids. Described in this paper is a quantitative comparison of thermal load on the external surface of turbine airfoil present in different power cycles the US Department of Energy plans for the next decade. The study is pursued with a computational simulation based on three-dimensional computational fluid dynamics (CFD) analysis. While the heat transfer coefficient has shown to vary strongly along the surface of the airfoil, the projected trends were relatively comparable for airfoils in syngas and hydrogen-fired cycles. However, the heat transfer coefficient for the oxy-fuel cycle is found to be substantially higher, by about 50–60%, than its counterparts in syngas and hydrogen turbines. This is largely attributable to the high steam concentration in the turbine flow. This overall suggests that advances in cooling technology and thermal barrier coatings are critical for the developments of future coal-based turbine technologies with nearly zero emission.

Two Phase Heat Transfer of Ammonia in a Mini/Micro Channel

2010 ◽  
Author(s):  
M. Hamayun Maqbool ◽  
Bjo¨rn Palm ◽  
R. Khodabandeh ◽  
Rashid Ali
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Experimental Results ◽  
Working Fluid ◽  
Internal Diameter ◽  
Vapour Quality ◽  
The Heat Transfer Coefficient

Experiments have been performed to investigate heat transfer in a circular vertical mini channel made of stainless steel (AISI 316) with internal diameter of 1.70 mm and a uniformly heated length of 245 mm using ammonia as working fluid. The experiments are conducted for a heat flux range of 15 to 350 kW/m2 and mass flux range of 100 to 500 kg/m2s. The effects of heat flux, mass flux and vapour quality on the heat transfer coefficient are explored in detail. The experimental results show that the heat transfer coefficient increases with imposed wall heat flux while mass flux and vapour quality have no considerable effect. Experimental results are compared to predictive methods available in the literature for boiling heat transfer. The correlations of Cooper et al. [1] and Shah [3] are in good agreement with our experimental data.

Thermal Investigation of Integrated Combustor Vane Concept Under Engine-Realistic Conditions

2016 ◽  
Author(s):  
Simon Jacobi ◽  
Budimir Rosic
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbines ◽  
High Speed ◽  
Secondary Flows ◽  
Experimental Measurements ◽  
Thermal Investigation ◽  
Nozzle Guide ◽  
The Heat Transfer Coefficient

This paper presents a thermal investigation of the Integrated Combustor Vane concept for power generation gas turbines with individual can combustors. This concept has the potential to replace the high-pressure turbine’s first vanes by prolonged combustor walls. Experimental measurements are performed on a linear high-speed cascade consisting of two can combustors and two integrated vanes. The modularity of the facility allows for the testing at engine-realistic high turbulence levels, as well as swirl strengths with opposing swirl directions. The heat transfer characteristics of the integrated vanes are compared to conventional nozzle guide vanes. The experimental measurements are supported by detailed numerical simulations using the inhouse CFD code TBLOCK. Experimental as well as numerical results congruently indicate a considerable reduction of the heat transfer coefficient (HTC) on the integrated vanes surfaces and endwalls caused by a differing state of boundary layer thickness. The studies furthermore depict a slight, non-detrimental shift in the heat transfer coefficient distributions and the strength of the integrated vanes secondary flows as a result of engine-realistic combustor swirl.

scholarly journals Characteristics of Refrigerant Boiling Heat Transfer in Rectangular Mini-Channels during Various Flow Orientations

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4891
Author(s):  
Magdalena Piasecka ◽  
Kinga Strąk
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Channel Length ◽  
Heat Transfer Process ◽  
Heated Wall ◽  
Working Fluid ◽  
Two Phase ◽  
Mini Channels ◽  
The Heat Transfer Coefficient

This paper reports the results of heat transfer during refrigerant flow in rectangular mini-channels at stationary conditions. The impacts of selected parameters on boiling are discussed, i.e., thermal and flow parameters, dimensions and orientation of the channels. Four refrigerants (FC-72, HFE-649, HFE-7000 and HFE-7100) were used as the working fluid. Research was carried out on the experimental set-up with the test section with a single rectangular mini-channel of 180 mm long and with a group of five parallel mini-channels, each 32 mm long. The temperature of the mini-channel’s heated wall was measured by infrared thermography. Local values of the heat transfer coefficient at the contact surface between the fluid and the plate were calculated using the 1D mathematical method. The results are presented as the relationship between the heat transfer coefficient and the distance along the mini-channel length and boiling curves. Two-phase flow patterns are shown. Moreover, the results concerning various refrigerants and the use of modified heater surfaces are discussed. The main factors influencing the heat transfer process were: mini-channel inclination to the horizontal pane (the highest heat transfer coefficient at 270° and 0°), using modified heater surfaces (especially electroerosion texturing and vibration-assisted laser No. 2 texturing) and working fluids (FC-72 and HFE-7000).

High Resolution Heat Transfer Measurement on Flat and Contoured Endwalls in a Linear Cascade

2012 ◽  
Author(s):  
Benoit Laveau ◽  
Reza S. Abhari ◽  
Michael E. Crawford ◽  
Ewald Lutum
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Transfer Coefficient ◽  
High Resolution ◽  
Transfer Coefficient ◽  
Gas Turbines ◽  
Transfer Data ◽  
Numerical Predictions ◽  
Endwall Contouring ◽  
The Heat Transfer Coefficient

In order to continue increasing the efficiency of gas turbines, a significant effort is being made to reduce losses induced by secondary flows in turbine stages. In addition to their impact on aerodynamic losses, these vortical structures are also the source of large heat transfer variations across the passage. A substantial reduction of the secondary flow losses can be achieved with a contoured endwall. However, a change in the vortical pattern can dramatically impact the thermal loads on the endwall and lead to higher cooling requirements in those areas. This paper focuses on heat transfer measurements made in a passage with either flat or contoured endwalls. The experimental data are supplemented with numerical predictions of the heat transfer data. The measurements are carried out on an isothermal endwall equipped with symmetric NACA airfoils. The paper presents measurements at M = 0.3 corresponding to a Reynolds number ReCax = 4.6×105. An infrared camera is used to provide high-resolution surface temperature data on the endwall. The surface is equipped with an insulating layer (Kapton) allowing the calculation of heat flux through the endwall. The heat transfer quantities, namely the heat transfer coefficient and the adiabatic wall temperature, are then derived from a set of measurements at different isothermal plate temperatures. The numerical predictions clarify the link between the change in the heat transfer quantities and the changes in the flow field due to endwall contouring. Finally numerically predicted heat transfer data are deducted from a set of adiabatic and diabatic simulations that are compared to the experimental data. The comparison focuses on the differences in the regions with endwall contouring, where a significant difference in the heat transfer coefficient between flat and contoured endwalls is measured, but under-predicted numerically.

Flow Boiling Heat Transfer Characteristics of a Minichannel Up to Dryout Condition

2009 ◽  
Author(s):  
Rashid Ali ◽  
Bjo¨rn Palm ◽  
Mohammad H. Maqbool
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Working Fluid ◽  
Flow Boiling Heat Transfer ◽  
The Heat Transfer Coefficient

In this paper the experimental flow boiling heat transfer results of a minichannel are presented. A series of experiments was conducted to measure the heat transfer coefficients in a minichannel made of stainless steel (AISI 316) having an internal diameter of 1.7mm and a uniformly heated length of 220mm. R134a was used as working fluid and experiments were performed at two different system pressures corresponding to saturation temperatures of 27 °C and 32 °C. Mass flux was varied from 50 kg/m2 s to 600 kg/m2 s and heat flux ranged from 2kW/m2 to 156kW/m2. The test section was heated directly using a DC power supply. The direct heating of the channel ensured uniform heating and heating was continued until dry out was reached. The experimental results show that the heat transfer coefficient increases with imposed wall heat flux while mass flux and vapour quality have no considerable effect. Increasing the system pressure slightly enhances the heat transfer coefficient. The heat transfer coefficient is reduced as dryout is reached. It is observed that dryout phenomenon is accompanied with fluctuations and a larger standard deviation in outer wall temperatures.

Flow Boiling Heat Transfer Characteristics of a Minichannel up to Dryout Condition

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Rashid Ali ◽  
Björn Palm ◽  
Mohammad H. Maqbool
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Working Fluid ◽  
Flow Boiling Heat Transfer ◽  
The Heat Transfer Coefficient

In this paper, the experimental flow boiling heat transfer results of a minichannel are presented. A series of experiments was conducted to measure the heat transfer coefficients in a minichannel made of stainless steel (AISI 316) having an internal diameter of 1.70 mm and a uniformly heated length of 220 mm. R134a was used as a working fluid, and experiments were performed at two different system pressures corresponding to saturation temperatures of 27°C and 32°C. Mass flux was varied from 50 kg/m2 s to 600 kg/m2 s, and heat flux ranged from 2 kW/m2 to 156 kW/m2. The test section was heated directly using a dc power supply. The direct heating of the channel ensured uniform heating, which was continued until dryout was reached. The experimental results show that the heat transfer coefficient increases with imposed wall heat flux, while mass flux and vapor quality have no considerable effect. Increasing the system pressure slightly enhances the heat transfer coefficient. The heat transfer coefficient is reduced as dryout is reached. It is observed that the dryout phenomenon is accompanied with fluctuations and a larger standard deviation in outer wall temperatures.

Turbulent Heat Transfer in the Separated, Reattached, and Redevelopment Regions of a Circular Tube

1966 ◽  
Vol 88 (1) ◽  
pp. 131-136 ◽  
Author(s):  
K. M. Krall ◽  
E. M. Sparrow
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flow Separation ◽  
Circular Tube ◽  
Turbulent Pipe Flow ◽  
Turbulent Heat Transfer ◽  
Working Fluid ◽  
The Heat Transfer Coefficient

Experiments were performed to determine the effect of flow separation on the heat-transfer characteristics of a turbulent pipe flow. The flow separation was induced by an orifice situated at the inlet of an electrically heated circular tube. The degree of flow separation was varied by employing orifices of various bore diameters. Water was the working fluid. The Reynolds number and the Prandtl number, respectively, ranged from 10,000 to 130,000 and from 3 to 6. The measurements show that the local heat-transfer coefficients in the separated, reattached, and redevelopment regions are several times as large as those for a fully developed flow. For instance, at the point of reattachment, the coefficients were 3 to 9 times greater than the corresponding fully developed values. In general, the increase of the heat-transfer coefficient owing to flow separation is accentuated as the Reynolds number decreases. The point of flow reattachment, which corresponds to a maximum in the distribution of the heat-transfer coefficient, was found to occur from 1.25 to 2.5 pipe dia from the onset of separation.

High Resolution Heat Transfer Measurement on Flat and Contoured Endwalls in a Linear Cascade

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Benoit Laveau ◽  
Reza S. Abhari ◽  
Michael E. Crawford ◽  
Ewald Lutum
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Transfer Coefficient ◽  
High Resolution ◽  
Transfer Coefficient ◽  
Gas Turbines ◽  
Transfer Data ◽  
Numerical Predictions ◽  
Endwall Contouring ◽  
The Heat Transfer Coefficient

In order to continue increasing the efficiency of gas turbines, a significant effort is being made to reduce losses induced by secondary flows in turbine stages. In addition to their impact on aerodynamic losses, these vortical structures are also the source of large heat transfer variations across the passage. A substantial reduction of the secondary flow losses can be achieved with a contoured endwall. However, a change in the vortical pattern can dramatically impact the thermal loads on the endwalls and lead to higher cooling requirements in those areas. This paper focuses on heat transfer measurements made in a passage with either flat or contoured endwalls. The experimental data are supplemented with numerical predictions of the heat transfer data. The measurements are carried out on an isothermal endwall equipped with symmetric airfoils. The paper presents measurements at M = 0.3, corresponding to a Reynolds number ReCax=4.6×105. An infrared camera is used to provide high-resolution surface temperature data on the endwall. The surface is equipped with an insulating layer (Kapton), allowing the calculation of heat flux through the endwall. The heat transfer quantities, namely the heat transfer coefficient and the adiabatic wall temperature, are then derived from a set of measurements at different isothermal plate temperatures. The numerical predictions clarify the link between the change in the heat transfer quantities and the changes in the flow field due to endwall contouring. Finally, numerically predicted heat transfer data are deduced from a set of adiabatic and diabatic simulations that are compared to the experimental data. The comparison focuses on the differences in the regions with endwall contouring, where a significant difference in the heat transfer coefficient between flat and contoured endwalls is measured but underpredicted numerically.

Investigation of the Degree of Augmentation of the Mass Transfer Coefficient of the Heat Transfer Medium in a Vortex Heat Exchanger of a Gas Pressure Regulating and Metering Station Heating System

2021 ◽  
Vol 25 (1) ◽  
pp. 53-65
Author(s):  
N. P. Grigorova ◽  
P. V. Monastyrev ◽  
E. G. Pakhomova ◽  
N. Ye. Semicheva
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Natural Gas ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Pressure ◽  
Heat Transfer Medium ◽  
The Heat Transfer Coefficient

Purpose of research. is to investigate the degree of augmentation of the mass transfer coefficient of a heat transfer medium in contact with a "spot" of liquid on the surface of the vortex blade when it is bombarded with dispersed contaminants in a vortex heat exchanger in order to identify a pattern that allows obtaining design values of the heat transfer coefficient of the heat transfer medium that have the best agreement with the experimental values provided in previously published articles [4, 6, 7].Methods. A complex analysis of the degree of augmentation of the mass transfer coefficient of the heat transfer medium on the surface of the vortex blade in a vortex heat exchanger based on the known theoretical positions and equations of heat and mass transfer processes.Results. The dependence of the augmentation of the mass transfer coefficient of the heat transfer medium in contact with the "spot" of liquid on the surface of the vortex blade when it is bombarded with dispersed contaminants was obtained, which allows obtaining the best agreement of the design and experimental values of the heat transfer coefficient in the vortex heat exchanger of a gas pressure regulating and metering station.Conclusion. The values of the heat transfer coefficient of the heat transfer medium calculated using the obtained dependence of the augmentation of the mass transfer coefficient of the heat transfer medium have a satisfactory convergence with the experimental data, which allows us to use this dependence in engineering calculations of the design parameters of the vortex heat exchanger used as a heat exchanger for the heating system of the working area of the gas pressure regulating and metering station. This technical solution allows not only saving natural gas as a source of heat generation, but also reducing the negative impact on the environment, since there is no need to burn natural gas. In this case, the production of thermal energy is carried out due to a regulated pressure drop of natural gas coming from the main line to consumers.

Sign in / Sign up

Export Citation Format

Share Document