The Optimization Design of the Nozzle Section for theWater Jet Propulsion System Applied in Jet Skis

The performance of a water jet propulsion system is related to the inlet duct,rotor,stator,and nozzle.Generally,the flow inlet design must fit the bottom line of the hull,and the design of the inlet duct is often limited by stern space.The entire section,from the rotor to the nozzle through the stator,must be designed based on system integration in that the individual performance of these three components will influence each other.Particularly,the section from the rotor to the nozzle significantly impacts the performance of a water jet propulsion system.This study focused on nozzle design and established referable analysis results to facilitate subsequent integrated studies on the design parameters regarding nozzle contour.Most existing studies concentrate on discussions on rotor design and the tip leakage flow of rotors or have replaced the existing complex computational domain with a simple flow field.However,research has yet to implement an integrated,optimal design of the section from the rotor to the nozzle.Given the above,our program conducted preliminary research on this system integration design issue,discussed the optimal nozzle for this section in-depth,and proposed design suggestions based on the findings.This program used an existing model as the design case.This study referred to the actual trial data as the design conditions for the proposed model.Unlike prior references’simple flow field form,this study added a jet ski geometry and free surface to the computational domain.After the linear hull shape was considered,the inflow in the inlet duct would be closer to the actual condition.Based on the numerical calculation result,this study recommends that the optimal nozzle outlet area should be 37%of the inlet area and that the nozzle contour should be linear.Furthermore,for the pump head,static pressure had a more significant impact than dynamic pressure.

Optimization and Sizing for Propulsion System of Liquid Rocket Using Genetic Algorithm

Flight vehicle conceptual design appears to be a promising area for application of the Genetic Algorithm （GA） as an approach to help to automate part of the design process. This computational research effort strives to develop a propulsion system design strategy for liquid rocket to optimize take-off mass, satisfying the mission range under the constraint of axial overload. The method by which this process is accomplished by using GA as optimizer is outlined in this paper. Convergence of GA is improved by introducing initial population based on Design of Experiments Technique.

Numerical and Experimental Studies on the Effect of Axial Spacing on Hydrodynamic Performance of the Hybrid CRP Pod Propulsion System

The hydrodynamic performance of a hybrid CRP pod propulsion system was studied by RANS method with SST k ？？ turbulence model and sliding mesh. The effect of axial spacing on the hydrodynamic performance of the hybrid CRP pod propulsion system was investigated numerically and experimentally. It shows that RANS with the sliding mesh method and SST k -ω turbulence model predicts accurately the hydrodynamic performance of the hybrid CRP pod propulsion system. The axial spacing has little influence on the hydrodynamic performance of the forward propeller, but great influence on that of the pod unit. Thrust coefficient of the pod unit declines with the increase of the axial spacing, but the trend becomes weaker, and the decreasing amplitude at the lower advance coefficient is larger than that at the higher advance coefficient. The thrust coefficient and open water efficiency of the hybrid CRP pod propulsion system decrease with the increase of the axial spacing, while the torque coefficient keeps almost constant. On this basis, the design principle of axial spacing of the hybrid CRP pod propulsion system was proposed.

A Comparative Study of Genetic Algorithm Parameters for the Inverse Problem-based Fault Diagnosis of Liquid Rocket Propulsion Systems

Fault diagnosis of liquid rocket propulsion systems （LRPSs） is a very important issue in space launch activities particularly when manned space missions are accompanied, since the safety and reliability can be significantly enhanced by exploiting an efficient fault diagnosis system. Currently, inverse problem-based diagnosis has attracted a great deal of research attention in fault diagnosis domain. This methodology provides a new strategy to model-based fault diagnosis for monitoring the health of propulsion systems. To solve the inverse problems arising from the fault diagnosis of LRPSs, GAs have been adopted in recent years as the first and effective choice of available numerical optimization tools. However, the GA has many control parameters to be chosen in advance and there still lack sound theoretical tools to analyze the effects of these parameters on diagnostic performance analytically. In this paper a comparative study of the influence of GA parameters on diagnostic results is conducted by performing a series of numerical experiments. The objective of this study is to investigate the contribution of individual algorithm parameter to final diagnostic result and provide reasonable estimates for choosing GA parameters in the inverse problem-based fault diagnosis of LRPSs. Some constructive remarks are made in conclusion and will be helpful for the implementation of GA to the fault diagnosis practice of LRPSs in the future.

Parameter Deviation Effect Study of the Power Generation Unit on a Doubly-Fed Induction Machine-based Shipboard Propulsion System

To lower the difficulty of fault protection,a doubly-fed induction machine based shipboard propulsion system(DFIM-SPS)that is partially power decoupled is presented.In such an intrinsically safe SPS architecture,a synchronous generator(SG)is employed for power generation,and the accuracy of the parameters of power generation unit(PGU)plays an important role in SPS stable operation.In this paper,the PGU parameter deviations are studied to evaluate the effects on system performance.The models of salient-pole SG,type DC1A excitation system(EXS)and DFIM are illustrated first.Besides,the corresponding control scheme is explained.For the 16 important parameters of PGU,up to 40%of parameter deviations are applied to implement parameter sensitivity analysis.Then,simulation studies are carried out to evaluate the parameter deviation effects on system performance in detail.By defining three parameter deviation effect indicators(PDEIs),the effects on the PGU output variables,which are the terminal voltage and output active power,are studied.Moreover,the increasing rates of PDEIs with different degrees of parameter deviations for the key parameters are analyzed.Furthermore,the overall system performance is investigated for the two most influential PGU parameters.This paper provides some vital clues on SG and EXS parameter identification for DFIM-SPS.

Novel Ship Propulsion System

As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship maneuverability becomes bad. A new ship propulsion system, integrated hydraulic propulsion （IHP）, is put forward to meet the development of modem ship. Principle of IHP system is discussed. Working condition matching characteristic of IHP ship is studied based on its matching characteristic charts. According to their propulsion principle, dynamic mathematic models of IHP ship and direct propulsion （DP） ship are developed. These two models are verified by test sailing and test stand data. Based on the software Matlab/Simulink, comparison research between IHP ship and DP ship is conducted. The results show that cabin arrangement of IHP ship is very flexible, working condition matching characteristic of IHP ship is good, the ratio of power to weight of IHP ship is larger than DP ship, and maneuverability is excellent. IHP system is suitable for engineering ship, superpower ship and warship, etc.

Reliability Modelling and Analysis of Satellite Propulsion System Based on Reliability Block Diagram and Extended Object-Oriented Petri Net

Modern satellite propulsion systems are generally designed to fulfill multiphase-missions.Traditional reliability modelling methods have problems of inadequate depict capacity considering complex systems such as satellite propulsion system.An extended object-oriented Petri net(EOOPN)method was proposed to facilitate the reliability modelling of satellite propulsion system in the paper.The proposed method was specified for modelling of phased mission system,and it could be implemented by generating combination of Petri net(PN)principles and object-oriented(OO)programming.The effectiveness of the proposed method was demonstrated through the reliability modelling of a satellite propulsion system with EOOPN.The major advantage of the proposed method is that the dimension of net model can be reduced significantly,and phased mission system at system,phase,or component levels can be respectively depicted.Furthermore,the state-space explosion problem is solved by the proposed EOOPN model efficiently.

Propulsion System of New-generation Small Rocket Passed First Test

Developed by the Academy of Aerospace Liquid Propulsion Technology (AALPT), the propulsion system for the new-generation light-lift liquid launch vehicle passed its first ground test firing on November 27, 2012 at the Beijing Institute of Aerospace Testing Technology. The event signifies that this is the only domestic static test-firing facility for rocket propulsion systems that can meet the development requirements for new-generation launch vehicles,

Advanced Concept Ramjet Propulsion System Utilizing In-Situ Positron Antimatter Derived from Ultra-Intense Laser with Fundamental Performance Analysis

The fundamental performance analysis of an advanced concept ramjet propulsion system using antimatter is presented. Antimatter is generated by ultra-intense laser pulses incident on a gold target. The scientific foundation for the generation of antimatter by an ultra-intense laser was established in the early 1970’s and later demonstrated at Lawrence Livermore National Laboratory from 2008 to 2009. Antimatter on the scale of 2 × 1010 positrons were generated through a ~1 ps pulse from the Lawrence Livermore National Laboratory Titan laser that has an intensity of ~1020 W/cm2. The predominant mechanism is the Bethe-Heitler process, which involves high-energy bremsstrahlung photons as a result of electron-nuclei interaction. Propulsion involving lasers through chemical rather than non-chemical interaction has been previously advocated by Phipps. The major utilities of the ultra-intense laser derived antimatter ramjet are the capability to generate antimatter without a complex storage system and the ability to decouple the antimatter ramjet propulsion system from the energy source. For instance the ultra-intense laser and energy source could be terrestrial, while the ramjet could be mounted to a UAV as a propulsion system. With the extrapolation of current technologies, a sufficient number of pulses by ultra-intense lasers are eventually anticipated for the generation of antimatter to heat the propulsive flow of a ramjet. Fundamental performance analysis is provided based on an ideal ramjet derivation that is modified to address the proposed antimatter ramjet architecture.

Fundamental Architecture and Analysis of an Antimatter Ultra-Intense Laser Derived Pulsed Space Propulsion System

Antimatter has been generated in large quantities by the Lawrence Livermore National Laboratory Titan laser. The Titan laser is an ultra-intense laser system on the order of approximately 1020W/cm2 with pulse durations of roughly 1ps. With the Titan laser incident on a high atomic number target, such as gold, antimatter on the scale of 2 × 1010 positrons are generated. Roughly 90% of the generated positrons are ejected anisotropic and aft to the respective target. The mechanisms for the laser-derived positron antimatter generation involve electron interaction with the nuclei based on bremsstrahlung photons that yield electron-positron pairs as a consequence of the Bethe-Heitler process, which predominates the Trident process. Given the constraints of the current and near future technology space, a pulsed space propulsion configuration is advocated for antimatter derived space propulsion, similar in concept to pulsed radioisotope propulsion. Antimatter is generated through an ultra-intense laser on the scale of a Titan laser incident on a gold target and annihilated in a closed chamber, representative of a combustion chamber. Upon reaching a temperature threshold, the closed chamber opens, producing a pulse of thrust. The implication of the pulsed space propulsion antimatter architecture is that the energy source for the antimatter propulsion system can be decoupled from the actual spacecraft. In contrast to conventional chemical propulsion systems, which require storage of its respective propulsive chemical potential energy, the proposed antimatter propulsion architecture may have the energy source at a disparate location from the spacecraft. The ultra-intense laser could convey its laser energy over a distance to the actual spacecraft equipped with the positron antimatter pulsed space propulsion system. Hydrogen is considered as the propulsive fluid, in light of its low molecular weight. Fundamental analysis is applied to preliminarily define the performance of the positron antimatter derived pulsed space propulsion system. The fundamental performance analysis of the antimatter pulsed space propulsion system successfully reveals the architecture is viable for further evaluation.

Fundamental Architecture and Performance Analysis of Photofission Pulsed Space Propulsion System Using Ultra-Intense Laser

Photofission enables a unique capability for the domain of non-chemical space propulsion. An ultra-intense laser enables the capacity to induce nuclear fission through the development of bre- msstrahlung photons. A fundamental architecture and performance analysis of a photofission pulsed space propulsion system through the operation of an ultra-intense laser is presented. A historical perspective of previous conceptual nuclear fission propulsion systems is addressed. These applications use neutron derived nuclear fission;however, there is inherent complexity that has precluded further development. The background of photofission is detailed. The conceptual architecture of photofission pulsed space propulsion and fundamental performance parameters are established. The implications are the energy source and ultra-intense laser can be situated far remote from the propulsion system. Advances in supporting laser technologies are anticipated to increase the potential for photofission pulsed space propulsion. The fundamental performance analysis of the photofission pulsed space propulsion system indicates the architecture is feasible for further evaluation.

A novel strategy of smart manipulation by micro-scale oscillatory networks of the reactionary zones for enhanced extreme thrust control of the next-generation solid propulsion systems

The main aim of this research is to get a better knowledge and understanding of the micro-scale oscillatory networks behavior in the solid propellants reactionary zones. Fundamental understanding of the micro-and nano-scale combustion mechanisms is essential to the development and further improvement of the next-generation technologies for extreme control of the solid propellant thrust. Both experiments and theory confirm that the micro-and nano-scale oscillatory networks excitation in the solid propellants reactionary zones is a rather universal phenomenon. In accordance with our concept,the micro-and nano-scale structures form both the fractal and self-organized wave patterns in the solid propellants reactionary zones. Control by the shape, the sizes and spacial orientation of the wave patterns allows manipulate by the energy exchange and release in the reactionary zones. A novel strategy for enhanced extreme thrust control in solid propulsion systems are based on manipulation by selforganization of the micro-and nano-scale oscillatory networks and self-organized patterns formation in the reactionary zones with use of the system of acoustic waves and electro-magnetic fields, generated by special kind of ring-shaped electric discharges along with resonance laser radiation. Application of special kind of the ring-shaped electric discharges demands the minimum expenses of energy and opens prospects for almost inertia-free control by combustion processes. Nano-sized additives will enhance self-organizing and self-synchronization of the micro-and nano-scale oscillatory networks on the nanometer scale. Suggested novel strategy opens the door for completely new ways for enhanced extreme thrust control of the solid propulsion systems.

Numerical Design and Performance Analysis of a Tug Boat Propulsion System

The aim of this project is to design and analyze the propulsion system for a tugboat for optimum performance. In so doing, certain approved procedures were followed;these procedures included getting the desired tugboat dimension, using ITTC methods, Gertlers charts, Bp charts etc. to estimate the bare hull resistance of the tugboat, estimating the effective power that must be employed to overcome this tug resistance. Numerical software code was developed to determine the various performance indicators of the propulsion system. The effective power was used as a basis for selecting the main engine and designing of a suitable propeller capable of propelling the tugboat for the various sea state were evaluated. Propeller cavitation was also put into consideration during this design. Hence in matching the engine to the propeller a series of calculations were done across a speed range of 300 - 500 rpm in other to effectively ascertain the engine-propeller matching point. The result shows that the point of engine-propeller matching is at 335 rpm and 2550 KW respectively. This provides a guide for the selection of a main engine with an acceptable sea service margins. All designs were done in accordance to classification organization and regulations.

The Low-Frequency Oscillation Restrain Method Research of Converter-Fed Multi-Phase Induction Motor Propulsion system

The inverter-fed induction motor drive system may become unstable at low frequencies and light load, and phase current and speed of the induction motor may oscillate periodically, which will threaten safety and reliability of the system. This paper chooses nine-phase induction motor simulated propulsion system as the research object, small disturbance model of three-phase induction motor is built, and average equivalent model of the converter is built by introducing switch function. On the basis above, small disturbance mathematic model of the whole system is obtained. As for the limitation of parameters adjustment method of restrain low-frequency oscillation, the restrain method combining current close-loop with dead-time compensation is put forward. Finally, the proposed restrain method is verified respectively on the built simulation and experimental analogue platform. And the simulation and experimental results indicate that the proposed method can not only satisfy the requirement of low-frequency oscillation restraining, but also be expanded widely, and the stability of the system can get improved greatly.

CASC 200mm Class Ion Propulsion System Ready for Application on Spacecraft

The 200mm class ion propulsion system(LIPS-200)developed by CAST subsidiary Lanzhou Institute of Vacuum Physics(LIP)has passed its 6000-hour accumulative ground test recently with 3000 times on-off switching throughout the test.It is capable of ensuring reliable in-orbit operation of a satellite for 15 years.China’s indigenous state-of-the-art electric propulsion system is ready to apply on spacecraft meeting the requirement for the

China Successfully Tested Propulsion System of Space Station's Lab Capsules

Shanghai Institute of Space Propulsion (SISP)under the Academy of Aerospace Propulsion Technology (AAPT)successfully tested the propulsion system of China's planned space station lab capsules. All the engines and system components worked well for the 2 hours of the 8 testprocedures,verifying the feasibility of the design plan for the propulsion system.

Swimmer with submerged SiO_(2)/Al/LiNbO surface acoustic wave propulsion system

Acoustic propulsion system presents a novel underwater propulsion approach in small scale swimmer.This study introduces a submerged surface acoustic wave(SAW)propulsion system based on the SiO_(2)/Al/LiNbO_(3) structure.At 19.25 MHz,the SAW propulsion system is proposed and investigated by the propulsion force calculation,PIV measurements and propulsion measurements.3.3 mN propulsion force is measured at 27.6 Vpp.To evaluate the miniature swimmer,the SAW propulsion systems with multiple frequencies are studied.At 2.2 W,the submerged SAW propulsion system at 38.45 MHz demonstrates 0.83 mN/mm^(2) propulsion characteristics.At 96.13 MHz and 24 Vpp,the movements of miniature swimmer with a fully submerged SAW propulsion system are recorded and analyzed to a maximum of 177 mm/s.Because of miniaturization,high power density,and simple structure,the SAW propulsion system can be expected for some microrobot applications,such as underwater drone,pipelinerobotand intravascularrobot.

Static aeroelasticity of the propulsion system of ion propulsion unmanned aerial vehicles

“Ionic wind”generators are used as the main propulsion system in ion propulsion unmanned aerial vehicles(UAVs).Owing to the large size and poor stiffness of the electrode array in the propulsion system,the electrode array is prone to deformation under the flight load.In this work,the thrust characteristics and static aeroelastic properties of“ionic wind”propulsion systems were analyzed in detail.The simulation model for an“ionic wind”propulsion system was established by coupling a two-dimensional gas discharge model with a gas dynamics model.The influences of electrode voltage,spacing,size,and shape on the performance of the propulsion system were investigated.The fluid-solid interaction method was used to solve static aeroelastic characteristics under deformation.The aerodynamic and thrust performances of the elastic state and the rigid state were compared.It was found that the operating voltage,the distance between two electrodes,and the emitter radius had greater impacts on the thrust of the propulsion system.The propulsion system had a small contribution to the lift but a large contribution to the drag.In the elastic state,the lift coefficient accounted for 12.2%,and the drag coefficient accounted for 25.8%.Under the action of the downwash airflow from the wing,the propulsion system formed an upward moment around the center of mass,which contributed greatly to the pitching moment derivative of the whole aircraft.In the elastic state,the pitching moment derivative accounted for 29.7%.After elastic deformation,the thrust action point moved upward by 28.7 mm.Hence,the no lift pitching moment is reduced by 0.104 N$m,and the pitching moment coefficient is reduced by 0.014,causing a great impact on the longitudinal trimming of the whole aircraft.

An atmosphere-breathing propulsion system using inductively coupled plasma source

CubeSats have attracted more research interest recently due to their lower cost and shorter production time.A promising technology for CubeSat application is atmosphere-breathing electric propulsion,which can capture the atmospheric particles as propulsion propellant to maintain longterm mission at very low Earth orbit.This paper designs an atmosphere-breathing electric propulsion system for a 3 U CubeSat,which consists of an intake device and an electric thruster based on the inductively coupled plasma.The capture performance of intake device is optimized considering both particles capture efficiency and compression ratio.The plasma source is also analyzed by experiment and simulation.Then,the thrust performance is also estimated when taking into account the intake performance.The results show that it is feasible to use atmosphere-breathing electric propulsion technology for CubeSats to compensate for aerodynamic drag at lower Earth orbit.

Optimization of a hydrogen-based hybrid propulsion system under aircraft performance constraints

This paper addresses the topic of the conceptual design of a regional aircraft with hybrid electric propulsion based on hydrogen fuel cells.It aims at providing an optimization-based method to design a hybrid propulsive system comprising two power sources(jet fuel and hydrogen)for the generation of the required propulsive power and at studying the impact of fuel cell technologies on the aircraft performances.Indeed,by performing optimizations for two hybrid propulsive systems using either low temperature or high temperature proton-exchange membrane fuel cells,this study provides a preliminary assessment of the impact of the fuel cell operating temperature on the system design and the overall aircraft performance.First,this paper gives a description of the baseline turboprop regional aircraft with a focus on its high speed and low speed flight performances which will serve as requirements for the design of the hybrid aircraft.Then,the hybrid electric architecture and the sizing models of the propulsion system are presented.Finally,optimizations are performed to design two parallel hybrid propulsive systems based on different fuel cells technologies and aimed at minimizing the block fuel per passenger over a mission of 200 n mile.Results show how the proposed methodology and models lead to design two propulsive systems capable of reducing the fuel consumption per passenger by more than 30%compared to the baseline aircraft.The study also shows that the choice of fuel cell operating temperature has a first-order impact on the total mass.