Characteristics Of Thruster Research Articles

Estimation of the required power of bow thruster based on numerical simulation

The paper presents the results of hydrodynamic characteristics of bow thruster (thrust coefficient K T , torque coefficient K Q ) in various pitch angles using RANSE method and compared to the experiment data provided by Maritime Advanced Research Centre (CTO S.A.), Gdansk, Poland. The required power of the bow thruster is estimated based on those numerical simulations. To get a better energy efficiency, the thrust-to-power ratio with pitch angle can be compared. The simulation of a rotating propeller is done using the sliding mesh approach. The k-epsilon turbulence model is utilized with commercial code ANSYS CFX when analyzing bow thruster performance. The results show that the difference between numerical and experiment results is quite high. Moreover, the power and the thrust-to-power ratio increase with the pitch angles and the bow thruster performs the best efficiency at the pitch angle of around 19°.

Experimental study on beam characteristics of μHT-1 thruster under operating conditions adjustment

The micro Hall thruster μHT-1 is designed for space gravitational wave detection missions, and the beam characteristics of the thruster are studied by experiments. A Faraday probe mounted on a three-dimensional moving platform is designed for diagnosing to obtain the beam current density distribution, and the operating conditions of the discharge voltage and the mass flow rate are adjusted in the range of 700∼1200 V and 0.1–0.5 sccm, respectively. In addition, the study further analyze the variation trends of total beam current, discharge current, utilization rate, divergence angle and others. The test results indicate that the μHT-1 thruster can work stably in a wide range of operating conditions, and the beam current expresses a good axisymmetric distribution. Meanwhile, the beam current density gradually decreases along the axial direction and spreads along the radial direction. The current utilization efficiency fluctuates from 53.4 % to 67.7 % when the power is adjusted in the range of 1.45–5.76 W, and the divergence angle increases from 41.3° to 56.7°. The total beam current of the thruster shows a linear increase characteristics with the enhancing of the anode flow and the discharge voltage.

Multiple ionization characteristics of hall thruster with large height–radius ratio and their effects

Increasing the specific impulse has become one of the main trends in the development of Hall thrusters and may be achieved by increasing the proportion of multiply charged ions in the plume. In this study, the multiple ionization characteristics of Hall thrusters with large height–radius ratios and their effects on the specific impulse and other performance parameters were examined via numerical simulations. The simulation results show that the proportion of multiply charged ions in a Hall thruster with a large height–radius ratio increases by 7.8 percentage points, compared with that of the traditional Hall thruster, and the multiply charged ions can obtain a higher average jet velocity under an accelerating voltage, thereby improving the specific impulse and thrust of the thruster. Further analyses show that a structure with a large height–radius ratio reduces the cooling effect of the channel wall on the electrons, and the increase in electron temperature effectively promotes the occurrence of the multiple ionization process. In addition, the smaller wall area and the larger magnetic field intensity in the near-wall region inhibit the electron near-wall conduction and prevent the potential negative effect of the increase in electron current caused by multiply charged ionization, which ensures a high level of efficiency. It was proved that multiple ionizations contribute positively to the specific impulse and efficiency of Hall thrusters with a large height–radius ratio. This serves as a reference for the high specific impulse design of Hall thrusters with large height–radius ratios and provides a new optimization perspective for improving the specific impulse of Hall thrusters.

Characteristics of microwave ECR ion thruster powered with plate antenna in cross-magnetic field: Standing wave, skin effect, and mode transition

In a 2.45 GHz electron cyclotron resonance xenon ion source powered with circular plate-antenna, a rapid evolution of radial plasma-profile with discharge power in a region below 35 W and the abrupt jump of ion beam current accompanied by sudden radial-expansion of discharge glow were observed. Based on analyses about quantified glow images captured from the end-view of the discharge chamber and the ion beam current against the discharge power, the fast evolution of the radial plasma-profile is attributed to the counteraction of standing wave and the skin effect, the coincidence of enhanced microwave absorption in the electron plasma resonance layer, and the transverse magnetic confinement of electrons. The jump of ion beam current and the sudden radial-expansion of discharge glow are confirmed to be originated from the extraordinary-wave discharge at the electron cyclotron resonance layer beyond the plate antenna when the skin effect is dominant.

Discharge characteristics of a Kilowatt Hall effect thruster with a variable channel

A kilowatt-order Hall effect thruster with a variable channel, the HET72-VC, is proposed. The discharge channel consists of an inner divergent annular segment and a cylindrical segment near the exit. A discharge comparison experiment was conducted on this thruster, in which the propellant gas is supplied along the axial direction and along the channel centerline. The results show that under the condition of gas supply along the channel centerline, both the current utilization and propellant utilization are higher, the plume divergence angle is smaller, the ion energy distribution curve moves to the high-energy portion, and the overall discharge performance, including the thrust and anode efficiency, is improved. A theoretical analysis shows that these results are attributed to the change in the ionization and acceleration characteristics caused by the different gas supply directions. The HET72-VC is demonstrated to be able to operate stably at an electric power of 2.5 kW; compared with those Hall effect thrusters with the same outer diameter or flow area of the channel, its thrust density and power density are both greatly improved. This provides a new perspective for the development of a high-power Hall effect thruster with a compact structure.

Thrust density characteristics of ion thruster

Thrust density distribution of ion thruster is an important factor that affects the orbit correction and station keeping of the spacecraft. Current empirical models mainly concern themselves with the overall thrust of the ion thruster, yet the thrust density distribution has not been fully understood. Hence it is necessary to investigate the thrust density characteristics of the ion thruster to devise the approach to optimizing the thruster performances. In this study, the thrust density characteristics of the ion thruster is analyzed and discussed by combining the empirical and theoretical methods. An ion thruster utilizes biased grids to extract ions from discharge chamber and accelerate them to high velocities, thereby forming a beam and generating thrust. In this paper, we analyze the working process of the ion thruster. The thrust expression as a function of beam micro-particle parameters is presented. Meanwhile the transport process of the plasma in the beam stream is simulated by the particle in cell-Monte Carlo (PIC-MCC) method for two-grid optics. The motion behavior of ions is modeled by the PIC method, while the collisions of particles are modeled by the MCC method. In the simulation, the particle trajectories are traced and the micro information about ejected charged ions is recorded with respect to singly charged ion, doubly charged ion and charge exchanged (CEX) ion. By analyzing the density and axial velocity of the charged particles in the beam stream, the thrust of the beam from a single grid hole can be calculated, based on which the thrust distribution of the thruster can be inferred by considering the distribution of plasma density at the exit of discharge chamber. Moreover, the above theoretical analysis of the thrust density is tested experimentally. The studies show that the thrust contribution percentages of the singly charged ion, doubly charged ion and CEX ion in the beam current are 84.63%, 15.35%, and 1.82%, respectively. Apparently, the main contributions to the thrust are made by the singly charged ions and doubly charged ions in the beam plasma, while the CEX ions have a trivial effect on the variation of the thrust. The distribution of the thrust density shows good symmetry along the central axis and it levels off after a fast decline in the radial direction. Comparisons of empirical and numerical results with the experimental results show that the empirical results have an error of about 4.1% and the numerical results have an error of about 2.8%. This indicates that the computational accuracy of our numerical model is better than that of the empirical model This work provides a reference for optimizing the thrust density uniformity of an ion thruster.

A simple model to determine the interrelation between the integral characteristics of hall thrusters

A simple model to determine the interrelation between the integral characteristics of Hall thrusters with an anode layer is proposed. The model includes the equation describing the balance of forces acting on the Hall current region, as well as the relationship between the current of accelerated ions and the rate of working gas consumption. For fixed geometrical characteristics of a specific Hall thruster, this model allows one to interrelate the main integral characteristics of the thruster, such as the accelerating voltage, the magnetic field, the propellant flow rate, and the current of accelerated ions. The results of calculations for TAL-WSF/D-55—one of the most widely used Hall thrusters with an anode layer—are presented. The domain of existence of the discharge in the channel of the Hall thruster is analyzed. It is shown that taking into account kinetic effects of neutral particle expansion and working gas preheating lead to a decrease in the current of accelerated ions and the engine thrust.

Numerical Study on Fundamental Characteristics of Electro-Hydrodynamic Thruster for Mobility in Planetary Atmosphere

Numerical Study on Fundamental Characteristics of Electro-Hydrodynamic Thruster for Mobility in Planetary Atmosphere

우주발사체 자세제어용 하이드라진 추력기의 정상상태 추력 특성

우주발사체 자세제어용 하이드라진 추력기의 지상연소시험을 수행하였다. 시험에 사용된 추력기는 추진제 주입압력 2.41 MPa (350 psia) 에서 정상상태 공칭추력 67 N (15 <TEX>$lb_f$</TEX>) 을 목표로 설계/제작 되었다. 개발모델 추력기의 성능특성 검토를 위해 정상상태 연소모드에서의 추력, 추진제 공급압력, 질량유량, 추력실 압력, 그리고 온도 등의 성능변수를 이용한다. 시험결과, 실제의 성능이 이론 요구규격 대비 89.1% 이상의 성능효율을 만족하는 것이 확인되었다. An ambient hot-firing test was carried out for the hydrazine thruster which may be employed in the space launch vehicles. The thruster is designed to produce 67 N (15 <TEX>$lb_f$</TEX>) of nominal steady-state thrust at an inlet pressure of 2.41 MPa (350 psia). A scrutiny into the performance characteristics of thruster is made in terms of thrust, propellant supply pressure, mass flow rate, chamber pressure, and temperature at the steady-state firing mode. As a result, it is ensured that the practical performance efficiencies are above 89.1% compared to its ideal requirements.

Some characteristics of the laser multi-pulse explosive type jet thruster

The results of further study of a laser multi-pulse explosive type jet are presented. The thrust produced by an unstationary gas flow within a nozzle due to laser induced blast waves is determined both theoretically and experimentally. The characteristics of a radiating gas flow are numerically analyzed by 1- and 2-D gasdynamic computer codes. The spatial structure of the gas flow and the radiation fluxes from a laser plasma are calculated. The radiation spectrum is estimated. The calculated pressure pulses on nozzles of various shapes are compared with the measured ones. Optimum nozzles, repetition rates and durations of the laser pulses and wavelengths of laser radiation providing the best propelling characteristics are established. Basing on an analysis of mechanical and thermal plasma actions on the nozzle walls some recommendations are given concerned with laser thruster design.

Experimental Investigation of the Characteristics of a Hollow Cathode MPD Arc Thruster

3 Bradshaw, P., The Effect of Initial Conditions on the Development of a Free Shear Layer, Journal of Fluid Mechanics, Vol. 26, Pt. 2,'1966, pp. 225-236. 4 Davies, P. O. A. L., in Free Shear Layers, AIAA Journal, Vol. 4, No. 11, Nov. 1966, pp. 1971-1978. 5 Sunyach, M. and Mathieu, J., Zone of a Two Dimensional Jet, International Journal of Heat and Mass Transfer, Vol. 12, 1969, pp. 1679-1697. Also Sunyach, M., Contribution a TEtude des Frontieres d'Ecoulements Turbulents Libres, D.Sc. thesis, May 1971, FUniversite Claude Bernard de Lyon. 6 Brown, G. and Roshko, A., The Effect of Density Difference on the Turbulent Mixing Layer, AGARD Fluid Dynamics Panel Specialists Meeting on Turbulent Shear Flows, Sept. 1971, London, England. 7 Spencer, B. W. and Jones, B. G., Statistical Investigation of Pressure and Velocity Fields in the Turbulent Two-Stream Mixing Layer, AIAA Paper 71-613, June 1971. 8 Champagne, F. H., Pao, Y. H., and Wygnanski, I. J., An Investigation of the Two-Dimensional Mixing Region, to be published. 9 Batt, R. G., Kubota, T., and Laufer, J., Experimental Investigation of the Effect of Shear Flow Turbulence on a Chemical Reaction, AIAA Paper 70-721, June 1970. 10 Sato, H., Experimental Investigation on the Transition of a Laminar Separated Layer, Journal of Physical Societv of Japan, Vol. 11, 1956. SUPPORTING ARM