Design of a Fuel Cell Powered Blended Wing Body UAV

2012 ◽  
Author(s):  
Dries Verstraete ◽  
Kai Lehmkuehler ◽  
K. C. Wong
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
Low Noise ◽  
Scale Model ◽  
Specific Power ◽  
Small Scale ◽  
Electrical Propulsion ◽  
Blended Wing Body

Small-scale electrically powered Unmanned Aerial Vehicles (UAVs) are currently in use for a variety of reconnaissance and remote sensing missions. For these missions, electrical propulsion is generally preferred over small internal combustion engines because of the low noise and IR signature, low vibration levels, ease of operational support, and physical robustness. A desire for longer endurance than is available from the current generation of batteries has motivated the development of fuel cell based hybrid electrical propulsion systems. These advanced powerplant designs often include implementation challenges that will require new development methods and tools. Fuel cells generally lead to very low fuel weight at a high specific energy (Wh/kg) but have low specific power (W/kg). A high specific power is required to improve aircraft performance and manoeuvrability. Aircraft concepts powered solely by fuel cells therefore require both extremely lightweight airframes with a large internal volume and low-power payloads, which remains a challenge for conventional airframe designs. A blended-wing-body (BWB) airframe has high aerodynamic and structural efficiencies, which therefore seem ideally suited for this new generation of power-plants. This paper presents the development and testing of a novel BWB fuel-cell powered UAV. The paper first describes the initial design steps that led to the current airframe design. The Mark 1 platform has been developed, with a half-scale model built and currently being flight-tested. Based on the flight test results, the airframe will be scaled up and optimised to accommodate the fuel-cell and its associated systems. This aircraft will then be tested with a standard electrical propulsion system to determine the airworthiness with the restricted fuel cell power output as well as the design of the take-off boost system. This paper reports on the design, analyses, and preliminary testing of a fuel cell powered BWB UAV.

Overview of Field Performance by UTC Fuel Cells’ Transportation Fuel-Cell Power Plants

2005 ◽  
Author(s):  
Praveen Narasimhamurthy ◽  
Zakiul Kabir
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Plants ◽  
Ambient Pressure ◽  
Polymer Electrolyte Membrane ◽  
Field Performance ◽  
Pem Fuel Cell ◽  
Low Noise ◽  
Transportation Fuel ◽  
Fuel Cell Stack

UTC Fuel Cells (UTCFC) over the last few years has partnered with leading automotive and bus companies and developed Polymer Electrolyte Membrane (PEM) fuel-cell power plants for various transportation applications, for instance, automotive, buses, and auxiliary power units (APUs). These units are deployed in various parts of the globe and have been gaining field experience under both real world and laboratory environments. The longest running UTC PEM fuel cell stack in a public transport bus has accumulated over 1350 operating hours and 400 start-stop cycles. The longest running APU fuel cell stack has accrued over 3000 operating hours with more than 3200 start-stop cycles. UTCFC PEM fuel-cell systems are low noise and demonstrate excellent steady state, cyclic, and transient capabilities. These near ambient pressure, PEMFC systems operate at high electrical efficiencies at both low and rated power conditions.

Assessment of the Potential of Combined Micro Gas Turbine and High Temperature Fuel Cell Systems

2002 ◽  
Author(s):  
Dieter Bohn ◽  
Nathalie Po¨ppe ◽  
Joachim Lepers
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Advanced Materials ◽  
Cell Systems ◽  
Micro Gas Turbine ◽  
Technological Assessment

The present paper reports a detailed technological assessment of two concepts of integrated micro gas turbine and high temperature (SOFC) fuel cell systems. The first concept is the coupling of micro gas turbines and fuel cells with heat exchangers, maximising availability of each component by the option for easy stand-alone operation. The second concept considers a direct coupling of both components and a pressurised operation of the fuel cell, yielding additional efficiency augmentation. Based on state-of-the-art technology of micro gas turbines and solid oxide fuel cells, the paper analyses effects of advanced cycle parameters based on future material improvements on the performance of 300–400 kW combined micro gas turbine and fuel cell power plants. Results show a major potential for future increase of net efficiencies of such power plants utilising advanced materials yet to be developed. For small sized plants under consideration, potential net efficiencies around 70% were determined. This implies possible power-to-heat-ratios around 9.1 being a basis for efficient utilisation of this technology in decentralised CHP applications.

scholarly journals Fuel Cells: The Next Evolution

MRS Bulletin ◽  
2005 ◽  
Vol 30 (8) ◽  
pp. 581-586 ◽  
Author(s):  
Robert W. Lashway
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Internal Combustion Engines ◽  
Materials Science ◽  
Electrical Conductance ◽  
Electrical Energy ◽  
Pure Oxygen ◽  
Combustion Engines ◽  
Hydrogen Fuel ◽  
Wide Range

AbstractThe articles in this issue of MRS Bulletin highlight the enormous potential of fuel cells for generating electricity using multiple fuels and crossing a wide range of applications. Fuel cells convert chemical energy directly into electrical energy, and as a powergeneration module, they can be viewed as a continuously operating battery.They take in air (or pure oxygen, for aerospace or undersea applications) and hydrocarbon or hydrogen fuel to produce direct current at various outputs. The electrical output can be converted and then connected to motors to generate much cleaner and more fuelefficient power than is possible from internal combustion engines, even when combined with electrical generators in today's hybrid engines. The commercialization of these fuel cell technologies is contingent upon additional advances in materials science that will suit the aggressive electrochemical environment of fuel cells (i.e., both reducing an oxidizing) and provide ionic and electrical conductance for thousands of hours of operation.

Design and Experimental Results of Small-Scale Rotary Engines

2001 ◽  
Author(s):  
Kelvin Fu ◽  
Aaron J. Knobloch ◽  
Fabian C. Martinez ◽  
David C. Walther ◽  
Carlos Fernandez-Pello ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Microelectromechanical Systems ◽  
Combustion Engine ◽  
Lithium Ion ◽  
Internal Combustion ◽  
Specific Power ◽  
Small Scale ◽  
Efficient Operation ◽  
Rotary Engine ◽  
Rotary Engines

Abstract A research project is currently underway to develop small-scale internal combustion engines fueled by liquid hydrocarbons. The ultimate goal of the MEMS Rotary Internal Combustion Engine Project is to develop a liquid hydrocarbon fueled MEMS-size rotary internal combustion micro-engine capable of delivering power on the order of milli-watts. This research is part of a larger effort to develop a portable, autonomous power generation system with an order of magnitude improvement in energy density over alkaline or lithium-ion batteries. The rotary (Wankel-type) engine is well suited for the fabrication techniques developed in the integrated chip (IC) community and refined by the MicroElectroMechanical Systems (MEMS) field. Features of the rotary engine that lend itself to MEMS fabrication are its planar construction, high specific power, and self-valving operation. The project aims at developing a “micro-rotary” engine with an epitrochoidal-shaped housing under 1 mm3 in size and with a rotor swept volume of 0.08 mm3. To investigate engine behavior and design issues, larger-scale “mini-rotary” engines have been fabricated from steel. Mini-rotary engine chambers are approximately 1000 mm3 to 1700 mm3 in size and their displacements range from 78 mm3 to 348 mm3. A test bench for the mini-rotary engine has been developed and experiments have been conducted with gaseous-fueled mini-rotary engines to examine the effects of sealing, ignition, design, and thermal management on efficiency. Preliminary testing has shown net power output of up to 2.7 W at 9300 RPM. Testing has been performed using hydrogen-air mixtures and a range of spark and glow plug designs as the ignition source. Iterative design and testing of the mini-engine has lead to improved sealing designs. These particular designs are such that they can be incorporated into the fabrication of the micro-engine. Design and fabrication of a first generation meso-scale rotary engine has been completed using a SiC molding process developed at Case Western Reserve University. The fabrication of the micro-rotary engine is being conducted in U.C. Berkeley’s Microfabrication Laboratory. Testing of the mini-engine has lead to the conclusion that there are no fundamental phenomena that would prevent the operation of the micro-engine. However, heat loss and sealing issues are key for efficient operation of the micro-engine, and they must be taken into account in the design and fabrication of the micro-rotary engine. The mini-rotary engine design, testing, results and applications will be discussed in this paper.

Conversion of Syngas From Biomass in Solid Oxide Fuel Cells

2006 ◽  
Author(s):  
Ju¨rgen Karl ◽  
Nadine Frank ◽  
Sotiris Karellas ◽  
Mathilde Saule ◽  
Ulrich Hohenwarter
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Liquid Metal ◽  
Waste Heat ◽  
Heat Pipes ◽  
Economic Feasibility ◽  
Small Scale ◽  
Cell Systems ◽  
Exhaust Heat ◽  
Integrated Gasification

Conversion of biomass in syngas by means of indirect gasification offers the option to improve the economic situation of any fuel cell systems due to lower costs for feedstock and higher power revenues in many European countries. The coupling of an indirect gasification of biomass and residues with highly efficient SOFC systems is therefore a promising technology for reaching economic feasibility of small decentralized combined heat and power production (CHP). The predicted efficiency of common high temperature fuel cell systems with integrated gasification of solid feedstock is usually significantly lower than the efficiency of fuel cells operated with hydrogen or methane. Additional system components like the gasifier, as well as the gas cleaning reduce this efficiency. Hence common fuel cell systems with integrated gasification of biomass will hardly reach electrical efficiencies above 30 percent. An extraordinary efficient combination is achieved in case that the fuel cells waste heat is used in an indirect gasification system. A simple combination of a SOFC and an allothermal gasifier enables then electrical efficiencies above 50%. But this systems requires an innovative cooling concept for the fuel cell stack. Another significant question is the influence of impurities on the fuel cells degradation. The European Research Project ‘BioCellus’ focuses on both questions — the influence of the biogenious syngas on the fuel cells and an innovative cooling concept based on liquid metal heat pipes. First experiments showed that in particular higher hydrocarbons — the so-called tars — do not have an significant influence on the performance of SOFC membranes. The innovative concept of the TopCycle comprises to heat an indirect gasifier with the exhaust heat of the fuel cell by means of liquid metal heat pipes. Internal cooling of the stack and the recirculation of waste heat increases the system efficiency significantly. This concept promises electrical efficiencies of above 50 percent even for small-scale systems without any combined processes.

Small Scale Reforming Separation Systems with Nanomembrane Reactors for Direct Fuel Cell Applications

2010 ◽  
Vol 12 ◽  
pp. 105-113 ◽  
Author(s):  
Savvas Vasileiadis ◽  
Zoe Ziaka
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Product Yield ◽  
Cell System ◽  
Membrane Reactors ◽  
Inorganic Membrane ◽  
Small Scale ◽  
Reaction Products ◽  
Molten Carbonate ◽  
Fuel Gas

Our recent communication focuses on small scale and nanoscale type engineering applications of alumina inorganic membrane reactors and reactor-permeator systems for the conversion of renewable and non-renewable hydrocarbons and methane rich streams into hydrogen rich gas for direct inner application and operation of fuel cell systems. This study elaborates on new nanomembrane reactors for the steam-methane/hydrocarbon reforming and water gas shift reactions, including work in the synthesis, manufacturing, modeling and operation of such microreaction systems. The projected small scale reactors, separators and overall reaction systems are of current significance in the area of multifunctional microreactor and nanoreactor design and operation in connection with the operation of fuel cells for transportation, stationary, and portable power generation applications. An added advantage of such systems is the reactive and separative operations of the fuel cell membrane-processor which are combined to convert the hydrocarbon with steam to valuable fuel gas for continuous fuel cell operation. Moreover, the nanomembrane systems under development have the unique characteristics to perform multiple operations per unit volume, such as to utilize beneficial equilibrium shift principles in reactant conversion and product yield through the removal of permselective species (i.e., hydrogen) via the inorganic membrane out of the conversion/reaction zone. In this way, improved hydrogen and product yields can be achieved which exceed the equilibrium calculated yields. Simultaneously, the reaction products, such as synthesis gas (i.e., H2, CO and CO2) at the reactor exit can be used as fuel in mostly solid oxide and molten carbonate fuel cells. The role of the alumina nanomembrane is also in the main conversion and upgrading sections of these feedstocks in order to overcome existing heat and mass transfer limitations and increase the overall efficiency of the microreactor-fuel cell system.

Effect of Inlet Flow Conditions on Flow Uniformity in a PEM Fuel Cell

2011 ◽  
Author(s):  
Lisa M. Grega ◽  
Steven Voinier
Keyword(s):  
Fuel Cell ◽  
Internal Combustion Engines ◽  
Plug Flow ◽  
Pem Fuel Cell ◽  
Small Scale ◽  
Inlet Flow ◽  
Velocity Statistics ◽  
Computational Data ◽  
Flow Configurations ◽  
Flow Maldistribution

The use of fuel cells as an alternative to traditional small scale power producing devices such as internal combustion engines or disposable batteries has continued to gain widespread acceptance. Flow maldistribution within cells in a stack continues to be an issue in fuel cell design and can adversely affect performance and longevity. Current research in this field has focused on effects of inlet configurations (plug flow versus circular inlet, for example) on the flow in a rectangular manifold and the resulting distribution into individual cells in the stack. In a typical small scale application, the piping which transports the reactant will contain bends in it. As these bends can introduce Dean vortices and flow asymmetries within the pipe flow, such conditions should be examined to determine whether they will affect the manifold flow and further impact cell maldistribution. A simplified scaled up model of a PEM fuel cell was fitted with different inlet flow configurations, including straight piping and piping containing a 90 degree bend prior to entering the manifold. Particle Image Velocimetry (PIV) was used to obtain mean and fluctuating velocity statistics within the manifold and in individual cells. These distributions will be compared with previous results obtained from this apparatus corresponding to a partially developed square inlet profile, as well as available experimental and computational data in the literature.

scholarly journals Success factors for demonstration projects of small-scale stationary fuel cells in residential buildings

2022 ◽  
Vol 334 ◽  
pp. 04007
Author(s):  
Guenter Simader ◽  
Patrick Vidovic
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Success Factors ◽  
Residential Buildings ◽  
Small Scale ◽  
Market Transformation ◽  
Japanese Industry ◽  
European Projects ◽  
Farm Program ◽  
Hydrogen Society

Worldwide small-scale micro-CHPs account for the largest share in the fuel cell market by units of installation (not by installed power output). Notably, the Japanese Ene-Farm program is responsible for over 400.000 micro-CHP fuel cell installations (until the end of June 2021). This is the largest worldwide deployment program and it reflects the long- and outstanding commitment of both the Japanese government and the Japanese industry to form a ‘Hydrogen Society’. In Europe, the situation is entirely different. European projects like PACE financed by the European joint undertaking for hydrogen and fuel cells give a positive impulse for fuel cell based micro-CHP, however it has to be judged as insufficient for a market transformation measure. Presently, only Germany, notably by the KFW433 program, is providing frame conditions for a rollout of fuel cell based micro-CHP systems. This article analyses the success factors for the implementation of Ene-Farm systems in Japan. It compares the different frame conditions of Japan and European countries like Austria and discusses the question whether an Ene-Farm project based on the Japanese success factors could be replicated in Austria. On a bird’s eye, a European perspective will be derived from the analysis.

Investigation of a Fuel Cell-Powered Blended Wing Body Airliner With Boundary Layer Re-Energization

2002 ◽  
Author(s):  
Vassilios A. Pachidas ◽  
Riti Singh
Keyword(s):  
Boundary Layer ◽  
Fuel Cell ◽  
High Speed ◽  
Preliminary Investigation ◽  
Specific Power ◽  
Fuel Burn ◽  
High Specific Power ◽  
Blended Wing Body ◽  
Center Body

The following study was undertaken on the assumption that hydrocarbon-based fuels may not be acceptable in the very long term, because of environmental concerns. A possible future fuel is hydrogen, and this study explores a novel proposition for a civil airliner using hydrogen fuel. The technical challenges of this preliminary investigation were: a) the integration of an electric power plant (Fuel Cell) into a Blended Wing Body (BWB) aircraft, and b) to investigate the possibility of reducing the aircraft’s profile drag by boundary layer re-energization. For the re-energization of the boundary layer and for propulsion during cruise, the study considered High-Speed/High Specific Power (HS/HSP) motors, situated at the trailing edge (TE) of the center body, driving fans. Re-energizing the boundary layer of the center body, would reduce the profile drag of the aircraft and hence, the total fuel burn. The take-off requirements of the aircraft were met, by high by-pass ratio (BPR) turbofan lift engines, operating on hydrogen, for a V/STOL (Pachidis, 2000b).

Molten Carbonate Fuel Cells for Retrofitting Postcombustion CO2 Capture in Coal and Natural Gas Power Plants

2018 ◽  
Vol 15 (3) ◽  
Author(s):  
Maurizio Spinelli ◽  
Stefano Campanari ◽  
Stefano Consonni ◽  
Matteo C. Romano ◽  
Thomas Kreutz ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Natural Gas ◽  
Co2 Capture ◽  
Power Plants ◽  
Combined Cycle ◽  
Co2 Separation ◽  
Molten Carbonate ◽  
Promising Alternative ◽  
Molten Carbonate Fuel Cells

The state-of-the-art conventional technology for postcombustion capture of CO2 from fossil-fueled power plants is based on chemical solvents, which requires substantial energy consumption for regeneration. A promising alternative, available in the near future, is the application of molten carbonate fuel cells (MCFC) for CO2 separation from postcombustion flue gases. Previous studies related to this technology showed both high efficiency and high carbon capture rates, especially when the fuel cell is thermally integrated in the flue gas path of a natural gas-fired combined cycle or an integrated gasification combined cycle plant. This work compares the application of MCFC-based CO2 separation process to pulverized coal fired steam cycles (PCC) and natural gas combined cycles (NGCC) as a “retrofit” to the original power plant. Mass and energy balances are calculated through detailed models for both power plants, with fuel cell behavior simulated using a 0D model calibrated against manufacturers' specifications and based on experimental measurements, specifically carried out to support this study. The resulting analysis includes a comparison of the energy efficiency and CO2 separation efficiency as well as an economic comparison of the cost of CO2 avoided (CCA) under several economic scenarios. The proposed configurations reveal promising performance, exhibiting very competitive efficiency and economic metrics in comparison with conventional CO2 capture technologies. Application as a MCFC retrofit yields a very limited (<3%) decrease in efficiency for both power plants (PCC and NGCC), a strong reduction (>80%) in CO2 emission and a competitive cost for CO2 avoided (25–40 €/ton).

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