One-Disk Nutating-Engine Performance for Unmanned Aerial Vehicles

Author(s):  
T. Korakianitis ◽  
L. Meyer ◽  
M. Boruta ◽  
H. E. McCormick

The nutating engine is a new type of internal combustion engine. The engine has unique advantages over conventional piston engines and gas turbines in small power ranges suitable for unmanned aerial vehicles (UAV), and other applications. This publication is the original presentation of the performance potential of the simplest version of the engine, a one-disk engine operating at constant compression ratio, for light airframe propulsion. In its basic configuration the core of the engine is a nutating non-rotating disk, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disk “nutates”, performs a wobbling motion without rotating around its axis. The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disk is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disk. The external combustion chamber enables the engine to use diesel fuel in small engine sizes, giving it unique capabilities for UAV propulsion. The performance of the one-disk engine configuration for flight Mach numbers from 0 to 1 and altitudes from 0 to 20 km is presented and discussed. The performance with equal compression and expansion volume is compared with the higher-efficiency version with expansion volume higher than compression volume. A companion paper examines multi-disk alternative engine configurations and load control schemes.

2004 ◽  
Vol 126 (3) ◽  
pp. 475-481 ◽  
Author(s):  
T. Korakianitis ◽  
L. Meyer ◽  
M. Boruta ◽  
H. E. McCormick

The nutating engine is a new type of internal combustion engine. The engine has unique advantages over conventional piston engines and gas turbines in small power ranges suitable for unmanned aerial vehicles (UAV), and other applications. This publication is the original presentation of the performance potential of the simplest version of the engine, a one-disk engine operating at constant compression ratio, for light airframe propulsion. In its basic configuration the core of the engine is a nutating nonrotating disk, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disk “nutates,” performs a wobbling motion without rotating around its axis. The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disk is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disk. The external combustion chamber enables the engine to use diesel fuel in small engine sizes, giving it unique capabilities for UAV propulsion. The performance of the one-disk engine configuration for flight Mach numbers from 0 to 1 and altitudes from 0 to 20 km is presented and discussed. The performance with equal compression and expansion volume is compared with the higher-efficiency version with expansion volume higher than compression volume. A companion paper examines multidisk alternative engine configurations and load control schemes.


Author(s):  
T. Korakianitis ◽  
L. Meyer ◽  
M. Boruta ◽  
H. E. McCormick

A new type of internal combustion engine and its thermodynamic cycle are introduced. The core of the engine is a nutating non-rotating disk, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disk nutates. The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disk is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disk. The accumulator and combustion chamber are kept at constant pressures. The engine has a few analogies with piston-engine operation, but like a gas turbine it has dedicated spaces and devices for compression, burning and expansion. The thermal efficiency is similar to that of comparably-sized simple-cycle gas turbines and piston engines. For the same engine volume and weight, this engine produces less specific power than a simple-cycle gas turbine, but approximately twice the power of a two-stroke engine and four times the power of a four-stroke engine. The engine has advantages in the 10 kW to 200 kW power range. This paper introduces the geometry and thermodynamic model for the engine, presents typical performance curves, and discusses the relative advantages of this engine over its competitors.


2021 ◽  
Vol 9 (2) ◽  
Author(s):  
Adrian Belmontes ◽  
Francisco Medina

Although a significant portion of unmanned aerial vehicles (UAVs) rely entirely on batteries, there are larger UAVs that operate by utilizing internal combustion engines. These special aircrafts ingest vast quantities of air, directly feeding the supply into the engine for combustion. The goal is to design and build an engine air particle separator (EAPS) for UAVs that employ combustion engines, to remove sand, dust, dirt, or any fine particles from the air being supplied to the engine. Although there are many constraints and restrictions to be considered, it is desired for the EAPS to be a single component, have the ability to connect to a specified intake collar, and fit within a given volume. Among other elements considered, the efficiency, pressure drop, areas of failure, and the selection of a material to build the separator were factored. Three methods of particle filtering were selected: inertial, centrifugal, and hypothetical pressure-barrier separation. To accomplish these goals, the principles of inertia, centrifugal forces, and pressure changes were used along with additive manufacturing – to be able to design and build complex geometries. Results were based on the three prototypes that were built and tested in an enclosure simulating the harsh weather environment and the force applied by the internal combustion engine from the UAV. These results showed that a centrifugal design was best suited for the purpose of the experiment with an experimental efficiency of 87% of the particles being separated from the air.


2020 ◽  
Vol 142 (6) ◽  
Author(s):  
S. Raviteja ◽  
P. A. Ramakrishna ◽  
A. Ramesh

Abstract Nitromethane has a stoichiometric air–fuel ratio of 1.7, which is 8.5 times lower than gasoline. For the same amount of air being drawn by the engine, more amount of nitromethane blends and hence more energy can be added. Methanol was used as a medium to mix nitromethane and gasoline, which are normally immiscible. Engine performance tests were carried out to study the effect of nitromethane addition to the methanol-gasoline blend. A large rise in engine torque and brake thermal efficiency (BTE) was obtained during the investigation. However, the brake specific fuel consumption (BSFC) also increased for the nitromethane blends. The engine parameters like spark timing, equivalence ratio, and compression ratio were optimized to further increase the engine power and also bring down the BSFC. A net torque improvement of 42%, BTE improvement of 35%, and BSFC rise of 9% were obtained by adding nitromethane and methanol in small fractions to gasoline. Combustion analysis was carried out using the cylinder pressure trace. High heat release rate and shorter combustion duration with nitromethane addition were observed. Emission measurements showed decrease in HC and CO emissions with nitromethane addition. However, a drastic rise in NO emissions was observed. Hence, it can be concluded that the specific power of small two-stroke spark ignition (SI) engines can be enhanced using nitromethane as a fuel additive to increase the payload of the unmanned aerial vehicles.


Author(s):  
T. Korakianitis ◽  
L. Meyer ◽  
M. Boruta ◽  
H. E. McCormick

The nutating engine is a new type of internal combustion engine with distinct advantages over conventional piston engines and gas turbines in small power ranges. The engine’s unique arrangement flexibility allows several alternative disk and shaft configurations, each selected for a different application. Variations in cycle temperature ratio and compression ratio during normal operation enable the engine to effectively become a variable-cycle engine, allowing significant flexibility for maximum efficiency or power or other optimizing function for on-ground stationary or for airborne applications. In its basic configuration the core of the engine is a nutating non-rotating disk, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disk “nutates”, performs a wobbling motion without rotating around its axis. The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disk is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disk. A companion paper examines the performance potential of the one-disk engine. This paper examines alternative engine configurations. The external combustion chamber enables the engine to operate on a variable compression ratio cycle. In addition, separate disks of unequal size are used for intake and expansion, resulting in distinct and significant power, efficiency, fuel flexibility, and arrangement advantages over conventional piston engines, over gas turbines, and over the basic nutating-engine configuration. The performance of these arrangements is examined for: on-ground power, on ground efficiency, (auxiliary power, automotive); and for small and light airframe applications for flight Mach numbers from 0 to 1 and altitudes from 0 to 20 km. This publication is the original presentation of the performance potential of several alternative configurations of the basic engine, such as multi-disk arrangements, combustion and exhaust disks of different size, and variable-compression ratio (variable cycle) configurations.


2018 ◽  
Vol 67 ◽  
pp. 02028
Author(s):  
Ardiyansyah Yatim ◽  
Ade Luthfi ◽  
Raden Chemilo

The Stirling engine is an external combustion where the fuel combustion process takes place outside the cylinder, at the combustion chamber or burner. Stirling engine offers flexibility of fuel used for the power generation hence is a potential substitute to fossil fuelled internal combustion engine and contribute toward more sustainable power generation. In this study a burner for Gamma V2-6 Stirling engine is designed and developed for a biogas-fuelled power generation system. The heat used to power the Stirling engine is obtained from combustion of biogas at the burner. The system has 5 kW capacity fuelled by 165 kg/day solid waste (biowaste) from local farm. The bio-digester needed is 20 m3. The combustion temperature of the burner is in the range of 600 to 1000°C. The required fuel input is 60,000BTU/hr or equivalent to 17 kW. The system requires constant heat from the combustion chamber hence a specific burner is designed to fulfil the purpose and accommodate biogas composition and optimum heat transfer to the engine. The burner is able to provide for simultaneous air preheater for lower fuel consumption leading to 37% lower fuel consumption.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3969
Author(s):  
Massimo Cardone ◽  
Bonaventura Gargiulo ◽  
Enrico Fornaro

This article presents a numerical model of an aeronautical hybrid electric propulsion system (HEPS) based on an energy method. This model is designed for HEPS with a total power of 100 kW in a parallel configuration intended for ultralight aircraft and unmanned aerial vehicles (UAV). The model involves the interaction between the internal combustion engine (ICE), the electric motor (EM), the lithium battery and the aircraft propeller. This paper also describes an experimental setup that can reproduce some flight phases, or entire missions, for the reference aircraft class. The experimental data, obtained by reproducing two different take-offs, were used for model validation. The model can also simulate anomalous operating conditions. Therefore, the tests chosen for the model validation are characterized by the EM flux weakening (“de-fluxing”). This model is particularly suitable for preliminary stages of design when it is necessary to characterize the hybrid system architecture. Moreover, this model helps with the choice of the main components (e.g., ICE, EM, and transmission gear ratio). The results of the investigation conducted for different battery voltages and EM transmission ratios are shown for the same mission. Despite the highly simplified model, the average margin of error between the experimental and simulated results was generally under 5%.


2004 ◽  
Vol 126 (2) ◽  
pp. 294-299 ◽  
Author(s):  
T. Korakianitis ◽  
L. Meyer ◽  
M. Boruta ◽  
H. E. McCormick

A new type of internal combustion engine and its thermodynamic cycle are introduced. The core of the engine is a nutating nonrotating disk, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disk nutates. The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disk is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disk. The accumulator and combustion chamber are kept at constant pressures. The engine has a few analogies with piston-engine operation, but like a gas turbine it has dedicated spaces and devices for compression, burning, and expansion. The thermal efficiency is similar to that of comparably sized simple-cycle gas turbines and piston engines. For the same engine volume and weight, this engine produces less specific power than a simple-cycle gas turbine, but approximately twice the power of a two-stroke engine and four times the power of a four-stroke engine. The engine has advantages in the 10 kW to 200 kW power range. This paper introduces the geometry and thermodynamic model for the engine, presents typical performance curves, and discusses the relative advantages of this engine over its competitors.


Author(s):  
Rao V. Arimilli ◽  
Kurt Erickson ◽  
Frederick T. Mottley ◽  
James C. Conklin

A revolutionary new concept internal-combustion engine called TurbX™ was invented and a prototype was built by an independent inventor, M. A. Wilson. Theoretically, the TurbX™ engine cycle can be represented by the Atkinson thermodynamic cycle with a continuous combustion process. Because of these attributes, this concept has the potential for higher fuel economy and power density relative to other internal combustion engine types. To evaluate the performance of this prototype, Oak Ridge National Laboratory and The University of Tennessee conducted an independent experimental study. Two series of tests were performed: cold-flow and fuel-fired tests. Cold-flow, compressed-air driven, tests were performed by pressurizing the combustion chamber with shop air to demonstrate the prototype performance of the turbine section. These results showed positive but unremarkable torque for combustion chamber air pressures above 300 kPa with a functional relationship illustrative of typical gas turbines with respect to shaft speed. The fuel-fired tests consisted of 26 constant-speed runs between 1800 and 9500 RPM. The experimental apparatus limited the maximum test speed to 9500 RPM. The TurbX™ engine produced no net output power for all fuel-fired tests conducted. The temperature measurements indicated that for most of the runs there was sustained combustion. However, even in runs where satisfactory combustion was observed, measured gage pressure inside the combustion chamber never exceeded 15.5 kPa. The lack of sufficient pressure rise inside the combustion chamber is indicative of excessive leakage of the combustion products through the preliminary prototype engine internals. Based on the results and the experience gained through this independent testing of this preliminary prototype, further development of this concept is recommended. Three major issues are specifically identified: 1) the internal components must be redesigned to reduce leakage, 2) combustion chamber design and 3) improve the overall aerodynamic performance of the engine internal components.


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