2019 Vol. 34, No. 5

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Design method for bearing-support structure and mechanical properties of high-speed rotor system
2019, 34(5): 961-970. doi: 10.13224/j.cnki.jasp.2019.05.001
Abstract PDF(2915KB) icon964 icon493
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For the optimization design of the structure and mechanical properties of the high-speed areo-engine rotor system, the influence of bearing-support properties (supporting point and supporting stiffness) on the rotor stiffness and dynamics was studied, and the correlation model for the bearing-support structure and rotor dynamics properties was established. The correlation between bearing-support parameters and mechanical properties, including the rotor stiffness, vibration, was analyzed. The influences of bearing-support properties and inertia load of rotating disc on rotor dynamics were quantitatively described, and the optimization design method and flow of bearing-support structure and rotor dynamics were presented. The numerical simulation result shows that the bearing-support structure properties method could determine the supporting point and supporting stiffness, and improve the stuffiness and vibration properties. This method is highly feasible, and beneficial to improve the design efficiency, and has important reference value for design of areo-engine overall structural layout and structural dynamics.
Numerical simulation method of the variability in tensile properties of SiC/SiC minicomposites
2019, 34(5): 971-979. doi: 10.13224/j.cnki.jasp.2019.05.002
Abstract PDF(2783KB) icon931 icon473
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An efficient numerical simulation method for calculating the statistical distribution function of mechanical properties of continuous fiber reinforced SiC/SiC ceramic matrix composites was established. The parameters of the probability distribution function of the constituents were assigned into a two-dimensional model of the representative unit cell and the corresponding mechanical properties of the unit cell were achieved. Afterwards, the attributes and material property parameters of the representative unit cell were homogenized into a two-dimensional model of minicomposites and macroscopic tensile stress-strain response of the minicomposites could be obtained. By conducting hundreds of computations in minicomposites with stochastic mechanical parameters in constituents, the probabilistic stress-strain curves were derived. It was found that the strength of SiC/SiC minicomposites satisfied the Weibull distribution well. In comparison with individual constituents as fibers and matrix, the Weibull modulus of the strength in the macroscopic minicomposites was much larger, indicating the decrease of the scatter in the strength. On the contrary, the scale parameter in the minicomposites was smaller than that of both constituents, implying the reduction of the strength with the highest probability density. Furthermore, with the increasing Weibull modulus of the strength in either fibers or matrix, the scale parameter of minicomposites strength increased simultaneously.
Thermomechanical fatigue on the nickel based single crystal superalloy DD6 with film cooling hole
2019, 34(5): 980-986. doi: 10.13224/j.cnki.jasp.2019.05.003
Abstract PDF(2270KB) icon892 icon551
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Turbine blades are subjected to thermal loads and mechanical loads simultaneously occurring during operation. Thermomechanical fatigue (TMF) is a major life-limiting factor for turbine blades. Film cooling holes within the blade introduced substantial stress concentration, which could dramatically reduce the lifetime. For quantification purposes, both smooth tubular specimens and notched specimens were utilized to perform TMF experiments. Results indicated that stress and fatigue life were in a good logarithmic linear correlation when the maximum stress changes within the range of 300-500 MPa and the hole could reduce the TMF life by 82.5%. Notched specimens with 〈010〉 and 〈110〉 oriented hole were tested respectively. It was found that the hole in 〈110〉 orientation had the weakest anti-TMF ability, since its life was only 40.0% of the 〈010〉 oriented notched specimen. The effect of drilling process was also studied. The results revealed that the life of notched specimen drilled by laser was 54.0% of the notched specimen drilled by electro-streaming drilling. The crack morphology demonstrated that TMF crack initiated from the film cooling hole edge which was severely oxidized and the crack propagated along the direction perpendicular to the edge of the hole.
Aeroengine load spectrum clustering method based on mission segment
2019, 34(5): 987-996. doi: 10.13224/j.cnki.jasp.2019.05.004
Abstract PDF(4827KB) icon754 icon477
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According to the classification problem of aeroengine mission profile, 31 flight mission profiles of a fighter engine were clustered. The flight altitude and flight Mach number were selected as the parameters of the flight mission profile, and the cluster scatter plot was generated according to the corresponding flight mission segment average, and the profile types were divided into five categories. Results showed that the low-altitude low-speed profile had the lowest mean value at the dimensionless flight altitude of 0－0.2 and the flight Mach number of 0.4－0.6. The high-altitude high-speed profile had the highest mean value at the dimensionless flight altitude of 1.2－2.2 and the flight Mach number of 1.0－1.8, with the flight mission profile. The dimensionless flight altitude was 0.2－1.2, and the flight Mach number was 0.6－1.0. The contour was further divided according to the profile characteristics; the difference between the flight height and the flight Mach number was different between different sections, which was beneficial to the section division. The difference between normal overload and speed was small, which was not conducive to the division of the profile. The proposed method can quickly and effectively cluster the aeronautical engine mission profile.
Numerical investigation of composite fan blade vibration characteristics due to blade-casing rub
2019, 34(5): 997-1009. doi: 10.13224/j.cnki.jasp.2019.05.005
Abstract PDF(5097KB) icon830 icon497
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A full three-dimensional composite fan blade rubbing vibration calculating model was established. A complete composite fan blade modeling method was used to establish composite fan blade and casing solid element models. The influence of the blades’ centrifugal stiffness was taken into consideration, Bezier surface was used to fit casing nodes. Rubbing phenomena of three blades with difference stacking sequences were studied under the assumption of a two-nodal diameter casing distortion. Results indicated that the stacking sequence pattern had a great impact on the blade rub-impact vibration characteristic at low rotational speeds. The rotating speeds of maximum amplitude and unstable vibration regions of blade with 90° layers were relatively low. The rubbing dynamic characteristics of the composite fan blade can be controlled by the stacking sequence, and when the rotating speed was close to the first-order mode resonance point of the blade caused by the third engine order, or close to the second-order mode resonance position of the blade caused by the sixth engine order, non-steady blade rubbing vibrations were generated. The method and results have certain guiding significance to the study of the rubbing dynamic characteristics of composite fan blades.
Experiment of rotor dynamics under fan blade off
2019, 34(5): 1010-1019. doi: 10.13224/j.cnki.jasp.2019.05.006
Abstract PDF(4994KB) icon776 icon471
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In order to research the dynamic response of the high bypass ratio turbofan engine under fan blade off, and finish the safety design better, the sudden unbalance experimental system with fan blade off device based on similarity theory were designed and experimental verification was finished. Research shows that the sudden unbalance experimental system has high similarity to some demonstration engines, which can finish the sudden unbalance experiment with good repeatability, clear mechanism and big unbalance, furthermore, it can simulate the fan blade off of the engine really. Through the experiment, it was found that when the large sudden unbalance occurred, the superharmonic frequency spectrum appeared and the impact coefficient didn’t show a linear relationship due to the limiting effect of the squeezed film damper, so the rubbing problem caused by the limiting should be concerned in the subsequent research.
Vibration characteristics analysis for helicopter main gearbox considering strutural flexibility
2019, 34(5): 1020-1028. doi: 10.13224/j.cnki.jasp.2019.05.007
Abstract PDF(4532KB) icon881 icon475
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The helicopter main gearbox was taken as the research object, the finite-element/lumped-parameter hybrid method was used to establish a hybrid dynamic model of a helicopter main gearbox, by considering the flexibility of the shaft and housing. The specific influence of the flexible housing structure on the vibration characteristics of the main gearbox was studied. Results demonstrated that, after considering the structure of the flexible housing, the natural frequency of each order was significantly decreased, the mode shape of the system was changed obviously, and the amplitude of the resonance peak of the system was decreased and the number of resonance speed was reduced. The flexible housing structure had little influence on the dynamic meshing force, but had a greater impact on the bearing reaction force. It can be divided into three categories: the fluctuation amplitude decreases, basically remains unchanged and increases, and the judgment criteria were given. The results lay a foundation for the vibration reduction, noise reduction and dynamic performance optimization of the helicopter main gearbox.
Calculation of natural characteristics and experimental methods of the clamp-pipe system
2019, 34(5): 1029-1035. doi: 10.13224/j.cnki.jasp.2019.05.008
Abstract PDF(2725KB) icon1002 icon537
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In view of the clamp-pipe system in aero-engine, the linear stiffness and angular stiffness of clamps with diameter of 8 mm was obtained based on self-designed experimental rig. The clamp was discretized into several springs according to the experimental results, and a dynamic model of the clamp-pipe system was proposed based on the finite element method. The measured stiffness of clamps and the finite element model was verified by comparing with the measured and simulated natural frequencies and corresponding frequency response functions. Furthermore, the effect of tightening torque on the natural frequencies of the clamp-pipe system was studied. The results show that the natural frequencies of the pipe increase with the tightening torque. For the clamps studied, the natural frequencies of the pipe gradually become stable value when the tightening torque is greater than 8 N·m.
Speciality assessment of sequential and concurrent aerostructuraloptimization based on coupled adjoint technique
2019, 34(5): 1036-1049. doi: 10.13224/j.cnki.jasp.2019.05.009
Abstract PDF(7684KB) icon896 icon455
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The RANS(Reynolds-averaged Navier-Stokes) equation, linear finite element analysis method, local mapping point link method and inverse distance weighting interpolation method were used to analyze the coupling between aerodynamic and structural variables. The gradients of merit function to aerodynamic and structure design variables were solved efficiently using aerostructural coupled adjoint technique. These modules were integrated with free form deformation module and gradient-based optimizer to form an aerostructural optimization design framework. A blend wing body aircraft was chosen to conduct sequential and concurrent aerostructural optimization. Results showed that the concurrent approach achieved 8.4% more range and 8.3% less structural weight, compared with the sequential approach on the same drag level. Moreover, the sequential approach had obvious shock wave on a significant portion of the outer wing. Meanwhile, the concurrent approach exhibited parallel pressure contour lines with roughly equal spacing indicating a shock-free result. All the results confirm that concurrent optimization for the design of the aeroelastic system provides significant advantages over the sequential approach. Given these improvements, the presented methods have the potential to be a useful tool in high flexibility aeroelastic design problems.
Optimization analysis for aerodynamic noise characteristics ofscissors tail rotor in hover
2019, 34(5): 1050-1060. doi: 10.13224/j.cnki.jasp.2019.05.010
Abstract PDF(4745KB) icon836 icon428
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A structure parametric design method of scissors tail rotor was established, in combination with areodynamic noise prediction technique based on CFD(computational fluid dynamics)/FW-H(Ffowcs Williams-Hawkings) equations and combinatorial optimization algorithm. The embedded grid method was developed to predict the flowfield of scissor tail rotor in steady flow. Based on the Navier-Stokes (RANS) equations, a high-effciency CFD simulation method was adopted for aerodynamic characteristics prediction of scissor tail rotor in hover. Based on the previous flowfield calculations, FW-H equations was established to predict the aerodynamic noise of scissor tail rotors. Then, to improve the hover efficiency and reduce the aerodynamic noise, optimization design for structural parameters of scissor tail rotor (scissors angle and shaft spacing) with constant thrust coefficient and constant pitch was conducted respectively. The genetic algorithm and surrogated model based on latin hypercube sampling (LHS) design and radial basis function (RBF) were combined as a hybrid optimization technique. The noise reduction mechanism of the tail rotor was obtained by these results. And the results show that, different combinations of scissors angle and shaft spacing can reduce the blade-vortex interaction phenomenon to cut down rotor blade-vortex interaction noise. Under the current calculation state, compared with conventional rail rotor, the hover efficiency of the optimized tail rotor increased by 16%, and the average sound pressure level decreased by 2.3 dB.
Sound generation by sideband instability in supersonic mixing layer
2019, 34(5): 1061-1068. doi: 10.13224/j.cnki.jasp.2019.05.011
Abstract PDF(3353KB) icon725 icon474
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To reveal the acoustic radiation mechanism of mixing layer under supersonic flow, and enhance the understanding, the parabolized stability equations (PSE) were performed to investigate the sound generation by sideband instability in a supersonic mixing layer. The nonlinear evolution of two initial disturbances and the fluctuation of difference component were analyzed. Mach wave radiation was quantified by an integral derived by Wu, which representd the detail of sound generation mechanism in far field. The results showed that the spectral broadening was due to the excitation of difference component and its sideband interaction. The generation of the difference component broadened the scope and enhanced the strength of Mach wave radiation. For fast mode, the difference component increases more rapidly with its frequency getting smaller, and the scope of Mach wave radiation gets wider in the meantime. However, for slow mode, the influence of frequency of difference component on Mach wave radiation is not obvious.
Influence of opening mode on performance characteristics of nacelle pressure relief door
2019, 34(5): 1069-1075. doi: 10.13224/j.cnki.jasp.2019.05.012
Abstract PDF(3206KB) icon703 icon437
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The performance of nacelle pressure relief door under different opening modes was numerically simulated, and the correctness of the numerical calculation was verified according to the experimental data in the NACA TN4007 report. On this basis, different Mach numbers (Ma=0.5, 0.7 and 0.9) and pressure ratios (Rp=1.2, 1.4 and 1.6) were compared for the effects on the discharge performance and force characteristics of the pressure relief door. The calculation results showed that under a certain Mach number, the discharge flow coefficient Cdr increased with the increase of pressure ratio. Under a certain pressure ratio, the discharge flow coefficient Cdr decreased with the increase of Mach number. In opening mode 2, discharge flow coefficient of the pressure relief door was slightly better than in opening mode 1. Since the pressure relief door was parallel to the flow in opening mode 1, the pressure relief coefficient of the pressure relief door was much smaller than that of opening mode 2, and the pressure coefficient of the pressure relief door was higher than that of opening mode 2, about twice of opening mode 2.
Characteristics investigation on supersonic inlet buzz with dynamic mode decomposition method
2019, 34(5): 1076-1084. doi: 10.13224/j.cnki.jasp.2019.05.013
Abstract PDF(3681KB) icon898 icon470
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Buzz phenomena of a typical supersonic inlet were studied with numerical simulations. The dynamic mode decomposition (DMD) method was introduced to analyze the flow characteristics of the little buzz and big buzz. The first order dynamic mode reflected the time-averaged flow field characteristics, and the second order dynamic mode showed the flow field features of the main frequency oscillation. In addition, the research on the relationship between little buzz and big buzz reveals that the flow of little buzz contains the oscillation characteristics of the big buzz, and little buzz regime is a transitional state from the steady flow field to the big buzz regime. During the evolution from the little buzz to the big buzz, some flow structures in the inlet are gradually weakened and tend to be stable, hence the overall flow field of the big buzz is more stable than that of the little buzz.
Characteristics of bump induced curved shock/boundary layer interaction under the sideslip condition
2019, 34(5): 1085-1093. doi: 10.13224/j.cnki.jasp.2019.05.014
Abstract PDF(3314KB) icon851 icon477
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The simulation method was used to investigate the flow field around the three-dimensional surface bump at designed Mach number 2 under the sideslip condition. Results show that as the sideslip angle increases, the pressure gradient on the windward side increases, and the high pressure center of the bump surface shifts toward the windward side. As a result, the strength of the vortex near the bump leading edge increases,which causes the loss of the total pressure recovery at windward side and finally makes the distortion of bump downstream flow field increase. At the same time, the surface flow topology of the bump shows that the conical similarity of the windward side separation zone increases as the sideslip angle increase, while the separation region on the bump leeward side evolves from a quasi-conical similarity to a quasi-cylindrical similarity gradually.
Test on influence of aromatic hydrocarbons on smoke emission characteristics in turboshaft engine
2019, 34(5): 1094-1100. doi: 10.13224/j.cnki.jasp.2019.05.015
Abstract PDF(1511KB) icon778 icon445
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In order to obtain the test data and influence of aromatic volume fraction on smoke emission，the smoke number test scheme of a turboshaft engine was designed. Aromatic hydrocarbons volume fraction of kerosene from different production regions was compared and analyzed. By adding toluene(C6H5CH3) to RP-3 kerosene, different volume fractions of aromatic hydrocarbons could be gained.The influence of aromatic hydrocarbon volume fraction on smoke emission was studied in domestic aeroengine field. The correlation of smoke number (SN) with concentration index (CI) was fitted according to the measured smoke number. Test results showed that the smoke emission index increased with the power state of turboshaft engine, and the smoke number was less than 40, which was superior to design requirements when turboshaft engine adopted baseline fuel. The increase of 3 percent in aromatic hydrocarbon volume fraction can lead to increase of 6 percent in smoke number. The test has provided an effective method for measurement and prediction of exhaust smoke and also beneficial experience and alternative fuels for suppressing smoke of turboshaft engines.
Icing scaling law at supercooled large droplet conditions
2019, 34(5): 1101-1110. doi: 10.13224/j.cnki.jasp.2019.05.016
Abstract PDF(4909KB) icon973 icon470
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Considering the limits of icing wind tunnels in simulating the SLD(supercooled large droplet) conditions in China, a SLD icing wind tunnel is an urgent realistic problem and its scaled theory needs to be solved. According to the dynamic characteristics and icing mechanism of the supercooled large droplets, six SLD icing scaling laws were proposed with the similarity theory and dimensionless analysis method. Some typical SLD icing conditions were chosen for verifying the SLD scaling law. Based on the FENSAP-ICE software, the ice shapes and other icing parameters were obtained, and also compared for the reliability analysis. Results showed that the coupled approach of impact parameter and ONERA method and the coupled approach of impact parameter and Ruff method had certain superiority and were in good agreement with the reference ice shapes in the test. Besides, the coupled approach of impact parameter and ONERA method was superior to the other methods when the median volumetric diameter was 171 μm.
Prediction method of lean blow-out limit based on a hybrid semi-empirical model
2019, 34(5): 1111-1118. doi: 10.13224/j.cnki.jasp.2019.05.017
Abstract PDF(2202KB) icon824 icon433
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A new method for predicting the lean blow-out performance of the combustor was proposed by combining the FV model with the simulation of reacting flows. The data of lean blow-out experiment of 5 combustors (two of which are through-flow combustors and the rest are reverse-flow combustors) showed that, when the value of model constant K was 1.35 to through-flow combustors, and 0.55 to reverse-flow combustors, the maximum uncertainties of the prediction method were less than ±20%. And compared with the Lefebvre model, the method proposed is much more applicable and precise for combustors of various structures.
Effects of incoming flow total temperature on mode transition boundary in dual mode scramjet combustor
2019, 34(5): 1119-1126. doi: 10.13224/j.cnki.jasp.2019.05.018
Abstract PDF(3392KB) icon811 icon432
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To estimate the effects of incoming flow total temperatures on mode transition boundary in a kerosene-fueled dual mode combustor, an test study was conducted using a direct-connected methane combustion heating test facility. The values of incoming flow total pressure at the isolator inlet should be kept at 1.05 MPa, the Mach number was about 2.0, the incoming flow total temperatures were 885, 1 085, 1 285 K, respectively. Combustor wall pressures were measured by pressure sensors; the mode of combustion was identified by calculating the Mach number at the isolator exit using a one-dimensional model. Test results indicated that, the locations of the combustor peak wall pressure were the same at different incoming flow total temperatures; there was a one-to-one relationship between the combustor peak pressure value, isolator near wall pressure distribution and shock train leading edge location; with the increase of incoming flow total temperature, the equivalence ratio of mode transition from supersonic to subsonic combustion rose up; under the same kerosene equivalence ratio, as the incoming flow total temperature increased, the combustor wall pressure dropped, the length of shock train got shorter.
Oil penetration mechanism induced by different bearing wall grooves
2019, 34(5): 1127-1136. doi: 10.13224/j.cnki.jasp.2019.05.019
Abstract PDF(3860KB) icon692 icon442
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High-speed angular contact ball bearing was used as the research object, and the groove was built on the inner wall of the bearing outer ring. The fluid and dynamics was used to analyze the gas-liquid two-phase flow of high-speed bearing wall groove model. The volume of fluid (VOF) model was applied to dynamically capture gas-liquid two-phase flow between the bearing rings. The movement process and distribution characteristics of lubricating oil under groove induction were analyzed, and the factors influencing the entry of lubricating oil were explored. The influences of groove shape, depth, direction and oil injection parameters on the volume fraction of lubricating oil in the cavity and raceway of high-speed bearings were studied. The research results show that during high-speed bearing injecting, through analysis of groove shape, depth and direction, the circular groove is suitable for high-speed bearings. When the groove depth is 0.8 mm, and the groove direction is 60 degrees, it is beneficial for lubricating oil to enter the bearing ring. The volume fraction of the effective lubricating oil and raceway oil in the cavity is the highest. Finally, the volume fraction of oil between grooved and non-grooved bearing chamber was measured and compared with the simulation results. It was found that the opening of wall grooves in the high-speed stage of bearing was conducive to the entry of lubricating oil, providing a new method for the lubrication design of high-speed bearing.
Prediction method and sensitivity analysis of the heat generation for an angular contact ball bearing
2019, 34(5): 1137-1144. doi: 10.13224/j.cnki.jasp.2019.05.020
Abstract PDF(2239KB) icon812 icon433
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Latin hypercube experimental design method was used to produce the sample data of structure parameters for the angular contact ball bearing NSK-7015C. The Newton-Raphson method was proposed for solving nonlinear equations composed of the equation of kinematic constraints, the ball equilibrium equations and the balance equations of the inner ring of the bearing. Then, the sample points corresponding the heat generation of the bearings were obtained. A combination method (active learning and Kriging-based Monte-Carlo simulation,AK-MCS) of the Kriging model and Monte Carlo was adopted to establish a function between sample points and the heat generation of the bearing. On this basis, a global sensitivity computational method was used to calculate the influence of structure parameters of the bearing on its heat generation. The results show that the differences between the prediction results of the heat generation for the bearing using AK-MCS method and the quasi-static analysis model of the bearing under the same structure parameters of the bearing are less than 0.003 W. This illustrates that the prediction results of the AK-MCS algorithm are highly accurate. The heat generation of the bearing is the most sensitive to the change of ball diameter,then the inner- and outer-ring raceway diameter take the second place, and the curvature radius of inner- and outer-ring raceway groove are the least. This research may bring forward the theoretical basis for the design optimization of structure parameters and selecting the machining accuracy of the bearing.
Effect of cage slipping on fault characteristic frequencies of aeroengine main-shaft bearings
2019, 34(5): 1145-1152. doi: 10.13224/j.cnki.jasp.2019.05.021
Abstract PDF(2437KB) icon855 icon465
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The relationship between the cage slip ratio and characteristic frequencies was obtained by theoretical deduction. The correctness of the derivation formulas was verified by the rotor experiment bench supported by cylindrical roller bearings. And the variation law of the slip ratio of the cage, the actual characteristic frequencies and the theoretical values deviations with the rotational speed were studied. Results showed that the slip ratio and the deviation tended to increase with the growth of the shaft rotating speed. The research conclusion has the guiding significance for the fault diagnosis of the aeroengine main-bearings.
Numerical simulation on flat baffle inlet distortion of axial compressor
2019, 34(5): 1153-1165. doi: 10.13224/j.cnki.jasp.2019.05.022
Abstract PDF(6031KB) icon881 icon514
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The coupling numerical simulation of the low-speed, high-subsonic, transonic axial compressor with the flat-baffle-type distortion generator was carried out respectively. The flow field characteristics of compressor under the flat-baffle-type distortion condition and the stall boundary of the different types of compressors were analyzed. It was found that the circumferential flow in the inlet plane of the low-speed compressor, the influence of the flat baffle angular vortex on the high subsonic compressor tip leakage’s flow path, and the change of passage shock wave’s intensity and location in the transonic compressor rotor passage were important factors of distortion flow to the stability boundary of different types of compressor respectively.
Design inquiry of an ultra-high-pressure-ratio component of multi-stage axial flow compressors
2019, 34(5): 1166-1177. doi: 10.13224/j.cnki.jasp.2019.05.023
Abstract PDF(5457KB) icon796 icon460
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For increasing the overall pressure ratio from 50∶1 to 70∶1 of the high bypass ratio turbofan engine, a 5-stage ultra-high-pressure-ratio axial-flow component with pressure ratio of 2.2∶1 was designed, and connected to the exit of a 10-stage high-pressure compressor with pressure ratio of 23∶1. The feasibility to improve the overall pressure ratio with a complete axial-flow configuration was explored. The design was implemented through the process including component 1-D overall aerodynamic design, S2 through-flow inverse problem and blade modeling and 3-D computational fluid dynamics verification. The specific methods such as positive pre-whirl at each stage, large-deviation-angle rotor tip and positive bowed stator were used in the process. Under the condition of achieving the prescribed aerodynamic design parameters, it’s recommended to set the rotor tip clearances to 0.2 mm rather than 0.3 mm, otherwise the compressor stall margin would drop significantly and its stable working range would be narrowed due to the geometric characteristics of large hub-tip ratio and the relatively larger rotor tip clearances. In the terms of structure, the design may lead to some issues that must be solved before the compressors enter into service, such as a huge number of blades and the higher machining costs of each stage.
Influence of anti-sputtering target on ion thruster back sputtering deposition
2019, 34(5): 1178-1184. doi: 10.13224/j.cnki.jasp.2019.05.024
Abstract PDF(1743KB) icon689 icon412
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Considering very large error of current back sputtering model, a model of higher accuracy was proposed. A improved ion current density model was used to calculate the back sputtering deposition in the 80 cm position deviating from the thruster while the Reynolds model had a big error. The calculated results agreed well with the experiment result. Then, the verified model was used to calculate the back sputtering deposition of bare chamber and the chamber with anti-sputtering target. The results showed that, the deposition rate of bare chamber case was 2.36×10-10 g/(cm2·s), while the anti-sputtering target shield case was 2.51×10-11 g/(cm2·s). It was clear that the back sputtering deposition yield with anti-sputtering target shield was an order of magnitude lower than the vacuum chamber without the anti-sputtering target.

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