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Effect of turbulence models on predicting convective heat transfer to hydrocarbon fuel at supercritical pressure

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Chinese Journal of Aeronautics 2016年第5期29卷 1247-1261页

作者： Tao Zhi Cheng Zeyuan Zhu Jianqin Li Haiwang National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics School of Energy and Power Engineering Beihang University

A variety of turbulence models were used to perform numerical simulations of heat transfer for hydrocarbon fuel flowing upward and downward through uniformly heated vertical pipes at supercritical pressure. Inlet temperatures varied from 373 K to 663 K, with heat flux rang- ing from 300 kW/m2 to 550 kW/m2. Comparative analyses between predicted and experimental results were used to evaluate the ability of turbulence models to respond to variable thermophysical properties of hydrocarbon fuel at supercritical pressure. It was found that the prediction performance of turbulence models is mainly determined by the damping function, which enables them to respond differently to local flow conditions. Although prediction accuracy for experimental results varied from condition to condition, the shear stress transport （SST） and launder and sharma models performed better than all other models used in the study. For very small buoyancy-influenced runs, the thermal-induced acceleration due to variations in density lead to the impairment of heat transfer occurring in the vicinity of pseudo-critical points, and heat transfer was enhanced at higher temperatures through the combined action of four thermophysical properties： density, viscosity, thermal conductivity and specific heat. For very large buoyancy- influenced runs, the thermal-induced acceleration effect was over predicted by the LS and AB models.

关键词： Buoyancy effect hydrocarbon fuel Supercritical pressure Turbulence models Variable properties

Artificial neural network analysis of the Nusselt number and friction factor of hydrocarbon fuel under supercritical pressure

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Propulsion and Power Research 2022年第3期11卷 325-336页

作者： Kaihang Tao Jianqin Zhu Zeyuan Cheng Dike Li National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing100191China

This paper presents the Nusselt number and friction factor model for hydrocarbon fuel under supercritical pressure in horizontal circular tubes using an artificial neural network(ANN)analysis on the basis of the back propagation *** derivation of the proposed model relies on a large number of experimental data obtained from the tests performed with the platform of supercritical flow and heat *** topology structures,training algo-rithms and transfer functions are employed in model *** performance of the optimal ANN model is evaluated with the mean relative error,the determination coefficient,the number of iterations and the convergence *** is demonstrated that the model has high prediction accuracy when the tansig transfer function,the Levenberg-Marquardt training algo-rithm and the three-layer topology of 4-9-1 are *** addition,the accuracy of the ANN model is observed to be the highest compared with other classic empirical *** relative error values of 4.4%and 3.4%have been achieved for modeling of the Nusselt number and friction factor respectively over the whole experimental data *** ANN model estab-lished in this paper is shown to have an excellent performance in learning ability and general-ization for characterizing the flow and heat transfer law of hydrocarbon fuel,which can provide an alternative approach for the future study of supercritical fluid characteristics and the associ-ated engineering applications.

关键词： Artificial neural network(ANN) Nusselt number Friction factor Supercritical pressure hydrocarbon fuel

Investigation of flow resistance characteristics of endothermic hydrocarbon fuel under supercritical pressures

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Propulsion and Power Research 2013年第2期2卷 119-130页

作者： Chunben Zhang Guoqiang Xu Hongwu Deng Kun Zhu National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing 100191China xi'an Aerospace Propulsion Institute Xi'an 710100China

The characteristics of flow resistance of a typical hydrocarbon fuel(RP-3)flowthrough adiabatic horizontal miniature tubes at supercritical pressures are experimentallyinvestigated for both laminar and turbulent *** experiments are conducted by using along tube measuring section and a short tube measuring section simultaneously in order toeliminate the effect of local pressure *** these experiments,the temperature of RP-3changes from(295 to 789)K and the reduced pressure(P/Pc,Pc=2.33 MPa)ranges from 1 to2.58,the mass flux is up to 1572.7 kg/(m^(2).s).Test results indicate that frictional pressuredrops for various supercritical pressures at the same mass flux can be considered as equalwith each other when the reduced temperature Tb/Tpc0.95,differenceappears and increases with the increase of Tb/***,the friction factor(f)of thesupercritical fluid for turbulent flow has a critical value at Tb/Tpc=1,the values of f at thispoint for all pressures and mass fluxes are equal with each ***,at the same massflux,there are two comresponding friction factors for the same Re,one is in the region of Tb/Tpc ***, classical conelations of frictionfactor is inapplicable when Tb/Tpc>0.95 at supercritical pressure and a new coelation hasbeen obtained based on the experimental data.

关键词： Supercritical hydrocarbon fuel Flow resistance Friction factor Pressure drop

Working state map of hydrocarbon fuels for regenerative cooling

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Propulsion and Power Research 2023年第2期12卷 199-211页

作者： Chen Zhang Hui Gao Jiajun Zhao Guice Yao Dongsheng Wen School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191 China bAircraft and Propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingbo 315100 China cInstitute of Thermodynamics Technical University of Munich85747Germany

Regenerative cooling by endothermic hydrocarbon fuel(EHF)is one of the most promising techniques for thermal management of supersonic or hypersonic *** to maintain the fuel working in proper states is an important issue to maximize the cooling potential of *** work proposes a novel working state map,including risking zone(RZ),thermal cracking zone(TCZ),supercritical zone(SupZ)and subcritical zone(SubZ),to differentiate possible working states of an EHF during regenerative *** n-decane flowing in a circular tube as an example,the boundaries of four zones are determined by numerical simulation covering different heat fluxes(0.2-4.0 MW·m^(-2))and mass flow rates(0.5-10.5 g·s^(-1))under two operating pressures(3.45 and 5.00 MPa).Empirical correlations for three boundary lines are obtained and the maximum cooling capacity is identified,as well as the identification of the pressure *** revelation of such new perspective of regenerative cooling is of great implication to the design and optimization of cooling system for future thermal management.

关键词： Regenerative cooling hydrocarbon fuel State map Chemical heat sink Thermal management

Analyses of surrogate models for calculating thermophysical properties of aviation kerosene RP-3 at supercritical pressures

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Science China(Technological Sciences) 2015年第3期58卷 510-518页

作者： XU KeKe MENG Hua School of Aeronautics and Astronautics Zhejiang University

Aviation kerosene is commonly used in combustion and regenerative engine cooling processes in propulsion and power-generation systems,including rocket,scramjet,and advanced gas turbine *** this paper,many surrogate models proposed in the open literature are examined for their applicability and accuracy in calculating thermodynamic and transport properties of the China aviation kerosene RP-3 at supercritical pressures,based on the extended corresponding-states *** enthalpy change from endothermic decomposition and low heating value from combustion of the jet fuel are also *** from a number of simple and representative surrogate models,which contain species components ranging from 1 to10,are analyzed in *** analyses indicate that a surrogate model with four species is the best choice for thermophysical property calculations under the tested conditions,with fluid temperature up to 650 K at various supercritical *** surrogate model is particularly accurate in predicting the pseudo-critical temperature of aviation kerosene RP-3 at a supercritical pressure.A simple surrogate model containing the n-decane species and a surrogate model containing 10 species are the other two acceptable *** work conducted herein is of practical importance for theoretical analyses and numerical simulations of various physicochemical processes at engine operating conditions.

关键词： thermodynamic property transport property hydrocarbon fuel combustion heat transfer pyrolysis

Latest development of double perovskite electrode materials for solid oxide fuel cells:a review

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Frontiers in Energy 2019年第4期13卷 770-797页

作者： Shammya AFROZE AfizulHakem KARIM Quentin CHEOK Sten ERIKSSON Abul K.AZAD Faculty of Integrated Technologies Universiti Brunei DarussalamJalan Tunku LinkGadong BE 1410Brunei Darussalam Department of Chemistry and Chemical Enineering Energy and MaterialsEnvironmental Inorganic ChemistryChalmers University of TechnologyGoteborg SE 41296Sweden

Recently,the development and fabrication of electrode component of the solid oxide fuel cell(SOFC)have gained a significant importance,especially after the advent of electrode supported *** function of the electrode involves the facilitation of fuel gas diffusion,oxidation of the fuel,transport of electrons,and transport of the byproduct of the electrochemical *** progress has been made in the development of alternative electrode materials with mixed conducting properties and a few of the other composite *** the operation of a SOFC,it is necessary to avoid carburization and sulfidation *** present review focuses on the various aspects pertaining to a potential electrode material,the double perovskite,as an anode and cathode in the *** than 150 SOFCs electrode compositions which had been investigated in the literature have been *** evaluation has been performed in terms of phase,structure,diffraction pattern,electrical conductivity,and power *** methods adopted to determine the quality of electrode component have been provided in *** review comprises the literature values to suggest possible direction for future research.

关键词： double perovskites electrode materials hydrocarbon fuel solid oxide fuel cells

Model validation and parametric study of fluid flows and heat transfer of aviation kerosene with endothermic pyrolysis at supercritical pressure

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Propulsion and Power Research 2015年第4期4卷 202-211页

作者： Keke Xu Hua Meng School of Aeronautics and Astronautics Zhejiang UniversityHangzhouZhejiang 310027China Collaborative Innovation Center for Advanced Aero-Engine Beijing 100191China

The regenerative cooling technology is a promising approach for effective thermal protection of propulsion and power-generation systems.A mathematical model has been used to examine fluid flows and heat transfer of the aviation kerosene RP-3 with endothermic fuel pyrolysis at a supercritical pressure of 5 MPa.A pyrolytic reaction mechanism,which consists of 18 species and 24 elementary reactions,is incorporated to account for fuel *** model validations are conducted against a series of experimental data,including fluid temperature,fuel conversion rate,various product yields,and chemical heat sink,fully verifying the accuracy and reliability of the *** of fuel pyrolysis and inlet flow velocity on flow dynamics and heat transfer characteristics of RP-3 are *** reveal that the endothermic fuel pyrolysis significantly improves the heat transfer process in the high fluid temperature *** the supercritical-pressure heat transfer process,the flow velocity significantly increases,caused by the drastic variations of thermophysical *** all the tested conditions,the Nusselt number initially increases,consistent with the increased flow velocity,and then slightly decreases in the high fluid temperature region,mainly owing to the decreased heat absorption rate from the endothermic pyrolytic chemical reactions.

关键词： Supercritical pressures hydrocarbon fuel Convective heat transfer fuel pyrolysis Regenerative cooling

Alternative fuels Derived from Solid Waste Plastics

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Journal of Environmental Science and Engineering 2011年第3期5卷 316-322页

作者： M. Sarker Department of Research ＆ Development Natural State Research Inc. Stamford CT 06902 USA

The demand for fossil fuel is at an all time high worldwide. Annually-30 billion barrels of petroleum is being consumed worldwide. In this busy society, transportation is vital and, for transportation, petroleum is a requirement. All the major forms of business, agricultural, exports and imports depend on transportation. There are three forms of major transportation： by ground, air and sea. These transportations require petroleum to function. Vehicles in the road require gasoline/diesel, airway transportation requires aviation fuel and sea transportation requires fuel oil and other forms of fuels. For not only transportation but, petroleum is required to make all kind of daily use plastics. If the consumption of petroleum continues this way, it will be finished in the near future. Emissions released from evaporation and combustion of these fuel contribute to many environmental and health problems, including emitting greenhouse gases that contribute immensely to global warming. Annually-7 billion tons of carbon is released to the environment due to burning of petroleum. Moreover, when the plastics are discarded into the landfill, it becomes waste plastic and since plastic is non-biodegradable, it can remain in the landfill for a long time. Waste plastics presence in the landfill causes environmental problems for example, it can cause soil to decay, pollute underground water resource and cause land to be infertile. Alternative source of energy created from solar, wind, hydrogen fuel, biomass fuel, bio-diesel, green diesel, bio-ethanol, and geo-thermal has been proposed as a solution to these problems and in future with further research, these alternative sources will play an important role in the field of alternative energy.

关键词： Alternative energy waste plastic hydrocarbon fuel NSR fuel thermal cracking.

Generation of Transportation fuel from Solid Municipal Waste Plastics

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Journal of Environmental Science and Engineering 2011年第1期5卷 57-62页

作者： M. Sarker M.M. Rashid A. Zaman and M. Molla Department of Research ＆ Development Natural State Research Inc. Stamford 06902 USA

Transportation fuels derived from imported fossil fuels are subjected to the price fluctuations of the global marketplace, and constitute a major expense in the operation of a vehicle. Emissions from the evaporation and combustion of these fuels contribute to a range of environmental and health problems, causing poor air quality and emitting greenhouse gases that contribute to global warming. Alternative fuel created from domestic sources has been proposed as a solution to these problems, and many fuels are being developed based on biomass and other renewable sources. Natural State Research, Inc. proposes a different alternative hydrocarbon fuel which is produced from abundant waste plastic materials. This fuel burns more efficiently and cleaner than commercial gasoline and diesel. The process exists to efficiently convert waste plastic into a reliable low cost source of fuel.

关键词： Waste plastic hydrocarbon fuel transportation fuel catalytic cracking gas chromatography differential scanning calorimetry.