High Propulsion Research Articles

Multiphase PMSM with Asymmetric Windings for Electric Drive

Multiphase permanent magnet synchronous motors (PMSM) are widely utilized in high power and high reliability electric propulsion systems. In electric propulsion systems, the motor may work at a low efficiency area for a long time, which increases energy consumption and reduces cruise range. In order to improve motor efficiency, this paper proposes a multiphase motor structure. The stator winding of proposed motor consists of three independent windings that have different rated speed and torque. In this paper, winding match mode, operation characteristic and efficiency characteristic are analyzed, and a torque distribution strategy with optimal efficiency is given. The results show that in propeller load such as electric aircrafts and ships, the proposed motor can reduce motor total loss and temperature rise in a drive cycle, which improves system efficiency, reliability and fault tolerance performance.

Optimum Design and Control of Marine Permanent Magnet Synchronous Motor

Marine electric propulsion has the advantages of wide range of speed regulation, easy installation and flexible operation’ so it is a high performance propulsion and superior in many respects compared with mechanical propulsion. Permanent magnet synchronous motor (PMSM) has a series of advantages such as fast response speed, strong overload capacity, high power density and high efficiency, so it is very suitable for marine propulsion system. In this paper, a kind of marine permanent magnet synchronous motor was optimized by using Maxwell software. At the same time, the direct torque control technology was simulated by using mathematical modelling. Direct torque control (DTC) is a high performance AC speed regulation technology. As long as the appropriate voltage vector is selected, the system can be controlled to quickly follow the given speed and adapt to the change of torque. The simulation results show the good performance for the marine permanent magnet synchronous motor in this paper so that it can fully meet the requirements in both speed characteristics and torque characteristics.

General Derivation Law With Torque-Free Achieving of Integral On-Board Charger on Compact Powertrains

Integrated charging for electric vehicles (EVs) is considered as a good transitional scheme to expand the mileage range under the battery capacity limit. It can save the costs and reduce the volume by replacing the on-board charger, and can increase the charging power by reusing the high power propulsion system. Then, the charging and propulsion system will therefore be light and compact. As the charging topology is based on the propulsion system, the design degrees of freedom are not very high, further resulting in limited application. And the laws of topological construction are lacking. Therefore, most of the integrated charging schemes are designed for a specific occasion and are difficult to adopt for other applications. In this article, a general derivation law with a unified design criterion is proposed to improve the generality of integrated charging, by considering the charging torque and equivalent filter inductance of the multiplexed converter and motor. The criterion is illustrated and analyzed in a specific scheme that is applied in the Toyota plug-in hybrid EV. The simulation results in a software-in-the-loop environment and experimental results in a down-scaled prototype are demonstrated to confirm the validity of the unified criterion and the effectiveness of the control schemes. It is suitable for the design of integrated charging solutions with multiphase power and multiphase motors.

A reliable data-driven model for Ablative Pulsed Plasma Thruster

Ablative Pulsed Plasma Thrusters (APPTs) are high specific impulse electric space propulsion system, but a reliable model equivalent of the experimental model is still unavailable. In this paper, a reliable model is developed based on APPT experimental data by using Machine Learning (ML) ecosystem. The goals of this study are to justify the accuracy and reliability of the newly built APPT model with the existing experimental and simulation model. For four sets of operating conditions, 600 experimental and simulation test operations are done. The experimental voltages and currents are measured with a high-voltage probe and a Rogowski coil, respectively. The simulation voltages and currents are gathered by running the respective simulation program. Comparison results show that the newly built APPT model has better accuracy and reliability than the simulated APPT model as compared to real APPT used in the experiment. This data-driven approach provides a novel way of designing a reliable alternative model of physical APPTs.

Linear burn rate of green ionic liquid multimode monopropellant

Multimode space propulsion systems are being proposed that integrate high specific impulse electric propulsion and high thrust chemical propulsion. The most important attribute of this concept is a shared propellant capable of both modes of propulsion, which enables mission flexibility. One promising approach is a catalytic monopropellant thruster paired with an electrospray electric thruster. Previous research has identified a green double-salt ionic liquid consisting of 41% wt. 1-ethyl-3-methylimidazolium ethyl sulfate and 59% wt. hydroxylammonium nitrate as a promising propellant candidate. In this work, the burn rate of this monopropellant is measured through pressure-based and high-speed imaging methods in a fixed-volume chamber pressurized across a pressure range from 0.5 to 10 MPa. Its performance is benchmarked by 80% wt. hydroxylammonium nitrate-water and nitromethane propellants. The burn rate of the multimode monopropellant is found to follow an exponential law given by rb=5.35exp1.11P between 0.5 and 3 MPa and is approximately constant at 142 ± 29 mm/s between 3 and 10 MPa.

Experimental validation of liquid hydrocarbon based fuel rich gas generator for high speed propulsion systems

For long duration hypersonic flight vehicles, research on high speed air-breathing propulsion systems has been progressing across the world for the past few decades. Ramjets/Scramjets fueled with hydrogen/liquid hydrocarbon fuels are the propulsion systems considered for different regimes of flight envelope. Dual Combustion Ramjet (DCR) engine is a prospective candidate for one of such kind of applications, where the engine is expected to work for a wider range of flight Mach number regime. It has a fuel rich subsonic dump combustor and a supersonic combustor, which work in tandem. In the present work, extensive experimental and analytical work has been carried out to develop a fuel rich gas generator often called as dump combustor suitable for operation from 20 to 28 km altitude and in the range of 4–6 flight Mach number. Connect pipe mode testing has been carried out by varying the throat area of dump combustor for Mach 4 conditions. Tests have been carried out with Jet-A fuel at different equivalence ratio and with fuel injection in different combination and stages. Fuel injection scheme used here is of shower head type in intake arm and a single simplex swirler with film cooling holes in the dump combustor. Study has been also carried out by varying the location of swirler along the combustor length. Combustor air entry conditions are simulated using H2–O2 based air heater and a test bed nozzle. An exhaustive amount of tests have been carried out to establish condition suitable for consistent ignition & sustained combustion in this highly fuel rich condition. A One dimensional (1D) mathematical model with NASA CEA interface has been developed to predict & compare the test performance. Sustained ignition is achieved for fuel flow rate of 0.8 kg/s and at an equivalence ratio of 0.8–0.9.

Melamine N-oxide based self-assembled energetic materials with balanced energy & sensitivity and enhanced combustion behavior

Development of advanced energetic materials with promising properties has been intensely-pursued over the past decades. However, traditional strategies for integrating fuel skeleton and oxidizing groups into an organic molecule are very difficult to balance the contradictory relationship between high energy and low sensitivity of energetic materials. In this work, we present a promising approach to develop advanced energetic materials through intermolecular assembly of nitrogen-rich triazine energetic compounds and high-energy oxidants. Under the direction of electrostatic potential and proton affinity calculations, a novel energetic compound 2,4,6-triamino-1,3,5-triazine-1,3-dioxide (TTDO) was rationally designed and synthesized. The easy and effective self-assembly of TTDO with high-energy oxidants afforded a series of novel advanced energetic materials with a good balance between energy and sensitivity. Among these self-assembled energetic materials, TTDOP (a self-assembled energetic material between TTDO and HClO4) showed a very high density (2.047 g cm−3 at 100 K), detonation properties (9284 m s−1 and 41 GPa) as high as that of HMX and better mechanical sensitivity (13 J and 144 N). Moreover, TTDOP exhibited great promise as a substitute for ammonium perchlorate (AP) in solid propellant formulations due to its high combustion and propulsion performances. This work opens a new avenue to develop intermolecular energetic materials with well balanced energy & sensitivity and versatile functionality.

Multifunctional Graphene-Based Additives for Enhanced Combustion of Cracked Hydrocarbon Fuels under Supercritical Conditions

ABSTRACT As a particulate fuel additive, functionalized graphene sheets (FGS), with and without the decoration of nanoparticles, provide a means to form stable colloids with liquid hydrocarbons, act as in situ catalysts, and prevent attached nanoparticles from agglomerating or sintering during heating. Recent pyrolysis experiments and simulations have shown the synergetic effect of Pt and FGS structures accelerating fuel conversion and hydrogen formation. In this paper, the role of graphene-based additives (with and without platinum (Pt) nanoparticles) on enhancing the ignition and combustion characteristics of cracked n-dodecane hydrocarbon fuels under supercritical conditions is examined. Supercritical ignition and combustion experiments were conducted using a high pressure and high temperature windowed combustion chamber coupled to a supercritical fuel pyrolysis reactor. The combustion experiments indicated that the presence of small amounts of particulate additives (100 ppmw) to the fuel can reduce ignition times and increase subsequent combustion rates. In particular, the addition of FGS-supported Pt nanoparticles reduced ignition delay times by nearly a factor of 3 (12.4 to 4.2 ms), increased spray spreading angles by approximately 32.0% (15.4 to 20.3°), reduced the flame liftoff length by 54.0% (1.74 to 0.8 mm), and demonstrated an increase in fuel conversion for a fixed reaction time of 35.0% relative to the pure fuel baseline. These results support the notion that nanostructured fuel additives have the potential to enhance both the heat sink capacity and combustion performance of liquid hydrocarbon fuels for their use in advanced high speed propulsion systems.

Design and development of the efficient anguilliform swimming robot— MAR

Propulsion of swimming robots at the surface and underwater is largely dominated by rotary propellers due to high thrust, but at the cost of low efficiency. Due to their inherently high speed turning motion, sharp propeller blades and generated noise, they also present a disturbance to maritime ecosystems. Our work presents a bio-inspired approach to efficient and eco-friendly swimming with moderate to high thrust. This paper describes the concept, development and experimental validation of the novel anguilliform robot MAR. With 15 elements making up the 0.5 m long propulsive section and driven by a single, speed-controlled brushless DC motor (BLDC), the robot creates a smooth continuous traveling wave for propulsion. Steering and autonomy are realized by an actuated head with integrated batteries that serves as a front-rudder. Almost neutral buoyancy paired with individually actuated pectoral fins furthermore enable submerged swimming and diving maneuvers. MAR accomplished high thrusts at a moderate power consumption in first performance tests. The achieved maximum velocity and the speed related efficiency (defined as the achieved speed over the power consumption m Ws−1) did not fulfill the expectations in the first tests (in comparison to commercial rotary thrusters), which can be largely attributed to the spatial limitations and an imperfect test setup. Nevertheless, the potential towards highly efficient and high thrust propulsion is visible and will be further investigated in future efforts.

Improving the efficiency and reliability of combined ship propulsions

Purpose. Ensuring high propulsion performance in a wide range of modes by optimizing the control of technological processes of energy use. Ways to improve energy efficiency and reduce the environmental impact of diesel propulsion systems were considered. A Container ship was choose, as example. A ship`s combined type propulsion unit is equipped with a synchronous machine, which is installed in the propeller shaft line and performs the function of a shaft generator. Its use is possible only when the vessel main diesel engine operates with a power above 40% of the nominal. In economy modes and in special conditions of vessel movement with lower power, the efficiency of the working process in the main engine decreases, fuel consumption per unit of power and time, as well as harmful emissions, increases. That is, in the existing composition, the propulsion unit does not meet a modern requirements for efficiency and environmental friendliness, and the practice of its use is not flexible enough. Methodology. To confirm the economic feasibility of modernization and the use of PTH mode, mathematical modeling of electromechanical transients in the "Ship network - vectordriven synchronous motor - load" system was performed. Results. Improving the safety and survivability of the ship (PTH mode) due to the additional propeller independent of the main engine of the electric drive. Reducing fuel consumption and harmful emissions into the environment, which increases the EEIO (Energy Efficiency Operational Index) of the vessel. Originality. The developed version of the modernization of the propulsion installation provides running mode of the vessel in special situations with reduced power by means of using the shaft generator as a motor. To implement this option, the propulsion installation need to be equipped additionally with a hydraulic coupling, which is allow to disconnect the main engine from the propeller shaft and to change over to electrical driving of ship propeller. The advantages of the propeller electric drive as the synchronous machine and frequency converter which is supplied from the ship's electrical network, are analyzed in comparison with the main diesel engine operates with low power. The block diagrams of the electric drive with vector control are given. Practical value. When the vessel is moving at a low speed, switching to PTH mode saves fuel (up to 118 kg / h), and increases the completeness of its combustion, since diesel generators operate at optimal load, unlike the main engine, which in this case is extremely unfavorable for the machine.

Sperm Micromotors for Cargo Delivery through Flowing Blood.

Micromotors are recognized as promising candidates for untethered micromanipulation and targeted cargo delivery in complex biological environments. However, their feasibility in the circulatory system has been limited due to the low thrust force exhibited by many of the reported synthetic micromotors, which is not sufficient to overcome the high flow and complex composition of blood. Here we present a hybrid sperm micromotor that can actively swim against flowing blood (continuous and pulsatile) and perform the function of heparin cargo delivery. In this biohybrid system, the sperm flagellum provides a high propulsion force while the synthetic microstructure serves for magnetic guidance and cargo transport. Moreover, single sperm micromotors can assemble into a train-like carrier after magnetization, allowing the transport of multiple sperm or medical cargoes to the area of interest, serving as potential anticoagulant agents to treat blood clots or other diseases in the circulatory system.

Review on Stationary CPT Technologies and Coil Designs for EVs

In the recent decade, the driving range of pure EVs with zero emission target has become a popular topic as the massive battery requirement for longer distance travels means higher vehicle cost and longer time of recharging periods. Stationary CPT charging solutions could be an alternative to reduce EVs weight, size and energy storage unit costs. Fortunately, with progressive success of low-power CPT charging applications proposed to be commercially produced in the past decade, hundreds of kilowatts level high-power CPT charging techniques for EVs are more and more expected to be an optimally suitable solution for recharging EV batteries, providing higher propulsion and delivering continuously longer driving range in the next generations of the EVs. The idea of deploying inductive coupling for EVs has acquired a lot of attentions in the last decade due to the contributions and advancements of power electronics, switching power supply, semiconductors, microprocessors, electrochemistry, material sciences, control technologies, electromagnetics and so on, despite many challenges to be addressed including EV manufacturing integration with CPT system under the chassis, infrastructure difficulties, system maintenance on both vehicle and transmitting ground sides, actual CPT performance with real-time coupling on real-world road. In order to ensure the realization and enhance the sustainability in transportation sector with the emerging CPT ideas, currently the stationary CPT charging solutions based on inductive power transfer (IPT) have been developed from laboratory level as a first step to the practical tests of commercial realizations. In a few industrial fields nowadays, some of the proposed CPT technologies with specific coupler coil designs have been expected for real-world applications. This article presents a state of the art of the CPT technologies and focuses on reviewing current coil designs for high-power contactless energy transfer for EVs in the literature.

Optimization and Analysis of Hybrid Electric System for Distributed Propulsion Tilt-Wing UAV

Hybrid electric distributed propulsion tilt-wing UAVs show unlimited application prospects due to their high propulsion efficiency and vertical take-off and landing capabilities. Aiming at the power requirements of distributed propulsion tilt-wing UAVs, this article presents an optimization design method for series hybrid electric propulsion systems suitable for this type of aircraft. Based on the flight conditions and constraints of various modes, the power demand models for distributed propulsion tilt-wing UAVs are established for vertical flight mode, transition mode, and forward flight mode. The hybrid electric power solving models of each component of the series hybrid electric system are established by analyzing the series hybrid power architecture and power transmission paths. The hybrid electric system weight model is mainly decomposed into the weight model of each component and the fuel consumption model. Based on power demand and energy demand, a mass model of components such as batteries, engines, generators, power management and distribution systems are established. Besides, the fuel consumption characteristic curve of the scaled engine is established using the Willans line formulation, and the fuel consumption calculation in the full flight profile is completed. The optimization of the series hybrid electric system of a 200kg-class distributed propulsion tilting wing UAV under two mission profiles of urban freight and mountain freight and the sensitivity of the optimized results to performance are presented. The results show that the proposed method can sensitively capture the significant influence of the adjustment of the mission profile and the changes in the performance requirements of each flight phase, and adapt to various application scenarios.

An Experiment on Solid Propellant Combinations; Evaluate the Propellant Properties using Ultrasonic Impulse Measuring System

Impulse force is the key for all high speed aero propulsion system. Solid propellants are uncontrollable once it ignited because it has the ingredients (fuel, oxidizer) for combustion within the chamber in which they are ignited. Since an entire solid propellant motor performance depends on propellant choice, chamber pressure, and nozzle design, the evaluation of propellant properties is highly needed. In the proposed Ultrasonic Impulse measuring system, the solid propellant motor, when fired, produces a thrust force which makes a bending moment in the simply supported beam. A sensitive Ultrasonic sensor will calibrate the bending moment, proportional to the Impulse force. The effective burning time is noted. Thermocouple reading, load cell reading, and the effective burning time value is used for calculating the mass flow rate, effective exhaust velocity, and specific impulse. The different fuel – oxidizer combinations with catalysers, binders are made. The small scaled propellant motor with length 0.12m, Diameter 0.025m, Exit Nozzle Diameter 0.003m, Empty Motor weight 20grams are used. The Recrystallation method is used for propellant preparation. The pyrotechnic ignition is adapted. The Grain test, Rope test are carried out. We have chosen high molecular weight, and low heat of formation value propellants. There are 4 different propellant combinations are tested with the proposed impulse measuring system. The Specific impulse reading of KNO3 + C12H22O11 + Al powder combination has highest value among all the propellants. It has 87seconds of specific impulse. The proposed impulse measuring system gives the reasonable readings with minimum error. We have compared the experimental results with the theoretical results and got the specific impulse of 90 seconds. The heat of formation of potassium nitrate and sucrose combination gives a low heat of formation value. The heat of combustion value and the characteristic velocity of the solid propellant combination (KNO3 + C12H22O11 + Al powder) are decreased.

Characteristics of swimming shelled Antarctic pteropods (Limacina helicina antarctica) at intermediate Reynolds number regime

Shelled Antarctic pteropods (aquatic snails nicknamed ``sea butterflies'') swim with a pair of parapodia (or ``wings'') in a high efficiency propulsion regime when the Reynolds number based on the flapping exceeds 35.

Design and Test of a High-Speed Double-Winding High Temperature Superconducting Synchronous Motor

The current carrying ability of the high temperature superconducting (HTS) material would be seriously influenced by the additional complex magnetic field. Because of this effect, the HTS material cannot be adapted in the field of high speed motors that work with high frequency current and strong magnetic field density. Therefore, this paper presents a novel HTS high speed motor system with high efficiency, high power density and high speed that could be adopted in the field of flywheel energy storage and high efficiency propulsion system. The one armature winding of the novel HTS high speed motor system is the superconducting coils, and the other armature winding is copper winding. Under this configuration, the motor with two armature windings is the doubly-fed motor. The two kinds of windings should operate in synchronous state. In this paper, a 2kW, 12000r/min high speed flywheel energy storage motor is designed. Surface magnetic field distribution of the superconducting winding and the characteristic of this type motor are detailed analyzed based on the current carrying ability of the HTS material. The new configuration of our novel HTS motor broaden the application of HTS materials in various electrical fields.

Testing and evaluation program of lab. scale hybrid propulsion system

The objective of the present paper is to prove the validity design and fully automatically operation of HPS, seeking to achieve its safety, low cost, and flexibility. In the stage of preliminary design, a coupling between experimental and theoretical work has been done, making use of available laboratory facilities and software packages (thermo-chemical calculation), to fully demonstrate all operating conditions. The HPS design includes the solid fuel grain configuration, essential operating parameters, oxidizer feed through control devices, measuring tools with calibration system, data recording and operating system. Commercial fuel materials as Polymethyl methacrylate (PMMA) and Polyethylene (PE) are used during experimental work to represent conventional generation fuel. Furthermore, new generation fuels as paraffin, beeswax, and paraffin with energetic additive metal (AL powder) are used. Gaseous oxygen is used as oxidizer. That may guide to design and fabricate high performance real rocket weapon or space propulsion system, targeting longer term storage and a propulsion system with available technology. The objective is extended to select appropriate ignition system (NiCr coil igniter) for laboratory firing of small-scale engine. One of the main problems (price, safety, available technology) of propulsion system today has been tackled. To that end, analysis has been established, to investigate the regression rate, solid fuel mass flow rate and combustion efficiency for each fuel grain group types.

Optimizing the Shape of a Compression-Ignition Engine Combustion Chamber by Using Simulation Tests

Abstract Modern solutions used in compression-ignition internal combustion engines are quite similar to each other. The use of high-pressure, direct fuel injection results in high combustion rates with controlled exhaust emissions. One of the combustion system quality criteria is to obtain adequately high thermodynamic indicators of the combustion process, which are obtained through, among others, the right combustion chamber geometry. Its shape influences the fuel atomization process, turbulence of fuel dose, evaporation and the combustion process. Optimizing the combustion chamber shape is one of the decisive factors proving the correct execution of the combustion process. This article presents the methodology of choosing the combustion chamber shape (changes of three selected combustion chamber dimensions) by using the optimization methods. Generating multidimensional data while maintaining the correlation structure was performed by using the Latin hypercube method. Chamber optimization was carried out by using the Nelder-Mead method. The combustion chamber shape was optimized for three engine load values (determined by the average indicated pressure) at selected engine operating conditions. The presented method of engine combustion chamber optimization can be used in low and high speed diesel propulsion engines (especially in maritime transport applications).

Flight Heritage of Ammonium Dinitramide (ADN) Based High Performance Green Propulsion (HPGP) Systems

AbstractThe flight heritage for ECAPS’ propulsion technology based of Ammonium DiNitramide (ADN), started 2010 with a successful 5 years on orbit demonstration mission of the PRISMA satellite. Since 2016, launches of satellites from 3 different continents continues to add to the flight heritage. Thirteen SkySat earth observation satellites with ADN‐based propulsion have added more than 28 years of accumulated flight heritage for LMP‐103S and ECAPS’ 1 N HPGP thrusters.

水上ジェットスキー推進装置の高圧水流による直腸肛門損傷の1例(A case of anorectal injury caused by the high pressure propulsion system of a water jet ski)

要旨 症例は18歳の男性。水上ジェットスキー（水上バイク）の後方座席に乗船し，加速した際に後方へ落水した。直後より腹痛，肛門痛，持続的な下血を認め，救急搬送された。初診時の肛門診察では6時方向に肛門から直腸にかけて約4cmの裂創があり，肛門は弛緩し，肛門収縮は認められなかった。腹部造影CTで腹腔内遊離ガス像と直腸周囲に造影剤の漏出を認めた。以上から水上ジェットスキー推進装置より噴出した高圧水流による直腸肛門損傷と診断し，緊急開腹術により腸管縫合術，人工肛門造設術，腹腔内ドレナージを施行した。術後は敗血症性ショックに陥ったがPMX–DHP（polymyxin B immobilized fiber column direct hemoperfusion），CRRT（continuous renal replacement therapy）によりショックから離脱し，術後経過は良好であった。第18病日の経肛門超音波検査で内肛門括約筋の不全断裂を認めたが，肛門収縮は残存していた。退院後は肛門括約筋訓練を行い肛門機能は徐々に回復し，受傷9か月後に人工肛門閉鎖術を実施した。水上ジェットスキーの高圧水流による直腸肛門損傷は稀であるが，出血や腹膜炎からショックに陥る場合がある。好発年齢である若年者の肛門機能に重篤な後遺症を残す可能性もあるため，早期より病態把握や肛門機能の評価を実施しなければならない。