The distribution characteristics of film cooling effectiveness of dustpan shaped holes at different positions of suction surface and pressure surface of turbine blade were studied by pressure sensitive paint (PSP) measurement technique. The effects of blowing ratio (blowing ratio of 0.5, 1.0, 2.0) and turbulence intensity (turbulence intensity of 0.62%, 16.0%) on film cooling effectiveness were analysed. The experimental results showed that the optimum blowing ratios of the dustpan shaped holes on the suction surface and pressure surface were around blowing ratio of 1.0 and 2.0, respectively. The dustpan shaped holes on the suction surface had higher film cooling effectiveness under low turbulence and medium blowing ratio (blowing ratio of 1.0). The dustpan shaped holes on the pressure surface had larger film coverage area and film cooling effectiveness under high blowing ratio and high turbulence. The film coverage area and spanwise averaged film cooling effectiveness on the suction surface were significantly higher than those on the pressure surface. And the film cooling performance of dustpan shaped holes at the position with large curvature was the worst on the pressure surface. The influence of turbulence on film cooling effectiveness was similar to that of blowing ratio. The enhancement of turbulence reduced the film cooling effectiveness on the pressure surface, but improved the film cooling performance on the suction surface under high blowing ratio, and reduced the sensitivity of the film cooling performance to the change of blowing ratio on the suction surface.

The establishment of hot air supply anti/de-icing test system in icing wind tunnel is the main means to carry out hot air anti/de-icing test. In order to meet the requirements of anti/de-icing system design and icing airworthiness certification for a series of domestic aircrafts, China Aerodynamics Research and Development Center (CARDC) carried out research on the hot air supply anti/de-icing test technology based on the 3 m×2 m large-scale icing wind tunnel, and independently developed the hot air supply anti/de-icing system. The digital valve flow control unit, electric heater unit, flow control unit and other test systems were designed and developed, and the test process and method were established. The perfect multi-channel hot sir supply anti/de-icing test technology was constructed, moreover, the dual-channel hot sir supply anti/de-icing test of a small aero-engine inlet was carried out. The test results indicated that the hot air supply anti/de-icing test system can simulate the hot air from the real compressor, allowing for multi-channel hot air supply test. The temperature control accuracy can reach ±1 ℃ and the flow control accuracy can reach ±1%. Meanwhile, it can provide a strong support for the anti/de-icing test system design and airworthiness certification of aircraft in China.

Considering the gas-solid two-phase flow problem of compressible pneumatic transport of large particles, the coupling calculation method of computational fluid dynamics (CFD) and discrete element method (DEM) was established. The flow field distribution in the hail ejection pipe was calculated by computational fluid dynamics, while the force and motion of hail were calculated by discrete element method according to aerodynamic parameters. When measuring hail velocity, a special measurement section was required to be installed at the outlet of the ejection tube. The difference between the measurement configuration and the open configuration was then compared and calculated. The results showed that the calculation results under the measured configuration were basically consistent with those under the open configuration, so the calculation and test under the measured configuration can support the design of continuous hail throwing device. Through the comparative calculation and test verification under three particle resistance models, the hail velocity calculated by Ergun model and di model was larger, and the hail velocity calculated by free flow resistance model was closest to the test measurement results. The calculated hail velocity differs by 8.9% from the test results, playing a guiding role in the design of hail continuous ejection device.

In order to investigate the details of the combustion organization of aluminum-containing high-energy-density hydrocarbon fuels in scramjet engine, a discrete phase model (DPM) and simplified reaction mechanism were used to numerically simulate the combustion flow process at different fuel injection positions. The results showed that when the seven injectors were used to inject fuel from the upper wall, the exit section formed a temperature distribution near the center of the upper wall from inside to outside, namely, relatively low temperature-warming-up to the highest temperature-cooling down. The lower oxygen concentration of the upper wall near the center area affected the progress of the reaction. Under the research conditions, as the distance between the injector and the inlet of the combustion chamber increased, the fuel specific impulse first increased and then decreased. In the research condition, the maximum specific impulse of fuel was 11092 m/s. The performance of the combustion chamber can be improved by changing the injection position of the fuel injected into the combustion chamber from the upper wall and optimizing the injector layout. After optimization, the maximum specific impulse increased by 12.68%.

To study the feedback of shear swirl and flame and its induced combustion instability mechanism in the lean direct injection (LDI) combustor, the dynamic response of flow field and flame excited with external excitation was studied by large eddy simulation (LES) combined with phase space reconstruction and modal decomposition. Comparing the experimental results of the flow field with the time averaged results of LES, it was found that the velocity distribution of the numerical calculation and the size and position of the vortex structure were in good agreement with the experimental results. The analysis of LES acquisition signal and instantaneous flow field showed that the pressure and heat release pulsation were in the limit cycle oscillation state. The contraction and expansion of the recirculation zone under velocity pulsation led to the periodic compression and relaxation of the fuel and heat release zone, resulting in quasi-periodic heat release pulsation. The modal decomposition of the data on the meridian plane showed that the velocity and heat release pulsation were mainly concentrated in the shear layer and the jet region. Meanwhile, the main pulsation modes were all longitudinal pulsations excited by the inlet velocity.

In order to improve the structural strength of heat exchanger and reduce the contact thermal resistance, a new concave-convex plate of frustum of a cone with hot stamping process was proposed. Numerical studies were carried out on the concave-convex structure channels of frustum of a cone with diameter height ratio of 3, 6 and 12 and on those of cylinder and spherical shape structure with diameter height ratio of 6. The flow and heat transfer performance and entropy generation distribution of channels with one and two concave-convex surfaces under different Reynolds numbers were studied. The results showed that the heat transfer distribution on the heat transfer wall of channels with one and two concave-convex surfaces was similar, but the flow and heat transfer performance of the former was better than that of the latter. When the Reynolds number increased from 5 000 to 20 000, the friction coefficient ratio and comprehensive heat transfer factor increased with the increasing diameter height ratio of frustum of a cone. When the diameter height ratio was constant, the comprehensive heat transfer factor of the channel was a spherical shape, frustum of a cone and cylinder concave-convex structure from large to small. In addition, the ratio of heat transfer and friction entropy generation decreased with the increase of Reynolds number.

Simulations were performed to study the downstream film cooling performance of round holes, fan-shaped holes, and laid-back fan-shaped holes at different heights on the suction surface of a rotor blade. Film holes were located at streamwise location of 17.8% and at 10%, 30%, 50%, 70% and 90% blade heights, respectively. The diameter of the round section of each shaped hole was 0.8 mm. Studies were conducted at rotational speed of 600 r/min, corresponding to rotational Reynolds numbers of 536 000. Five blowing ratios of 0.50, 0.75, 1.00, 1.25 and 1.50 were involved. Results showed that under the effects of passage vortex and tip leakage flow, inward film deflection trend towards the mid-span on the suction surface differed at different blade heights, corresponding to different degrees of structural asymmetry of counter rotating vortex inside film trajectories at different blade heights. With the increase of blowing ratio, the height at which the highest film cooling effectiveness appeared gradually moved upward. The introduction of fan-shaped hole and laid-back fan-shaped hole weakened the normal momentum of the jet at the hole exit and improved film coverage and film cooling effectiveness.

Numerical decoupling method was used to quantitatively analyze the relationship between the overall cooling effectiveness of impingement-effusion model and the internal cooling, bore cooling and coolant coverage. The blowing ratios were 0.25, 0.5, 1 and 1.5. It was found that the blowing ratio had a significant effect on the comprehensive cooling effect of the impact divergence model. When the blowing ratio increased from 0.25 to 1.5, the overall cooling effectiveness increased by 57.9%. The stagnation region of impingement jet was mainly dominated by internal cooling. The region where the bore cooling had the greatest influence on the overall cooling effectiveness was located upstream of the film hole outlet, and the influence of bore cooling along the streamwise direction was gradually reduced. The influence of coolant coverage on the overall cooling effectiveness gradually accumulated along the streamwise direction, and the influence near the third film hole outlet was the largest. The influence in the downstream of film hole was greater than that in the region away from the film hole. When the blowing ratio increased to 1, the effect of bore cooling on the overall cooling effectiveness exceeded that of coolant coverage.

The flow field of a gas-solid two-phase rotating detonation engine taking aluminum powder as fuel and air as oxidant with one step reaction was investigated by two-dimensional numerical simulations at different equivalence ratios. Results showed that the velocity of the detonation wave decreased from 2070 m/s to 1690 m/s and detonation pressure decreased from 5.67 MPa to 4.87 MPa when the equivalence ratio increased from 0.6 to 1.4, because the average local equivalence ratio increased from 0.929 to 2.093, which was caused by incomplete overlapping of trigonal zones between air and particles because of the injection velocity difference between air and particles. The flow field was similar to that in gas phase rotating detonation engines. However, unique distribution characteristics, including two particle groups, four particle bands and gaps among them due to the interaction between gas phase and solid phase, were obtained.

In order to reduce the temperature and infrared radiation intensity of the diverter at the outlet of the mixing duct of the integrated infrared suppressor, a double mixing duct and a diverter with cooling structure were designed. Through CFD and numerical simulation of the spatial distribution of infrared radiation intensity, the effects of inlet flow rate of forced cooling, outlet shape of deflector and number of valves on the infrared radiation intensity of exhaust jet and exhaust mixing duct were studied. The calculation results showed that compared with the reference model (single-layer mixing duct, no cooling of the deflector), the structure of double-layer mixing duct and deflector can effectively reduce the visible surface high-temperature region of the deflector, and the infrared radiation intensity of the deflector itself can be reduced by 82.9%. The wave disc at the outlet of the deflector can induce streamwise vortex pairs, and the enhanced cooling air can be mixed with the exhaust wake at the outlet of the mixing duct. Compared with the benchmark model, the infrared radiation intensity of the exhaust can drop up to 68.2%, and the overall radiation intensity of the mixing duct and its exhaust can drop up to 86.4%. The exhaust infrared radiation intensity and the overall radiation intensity decreased gradually with the decrease of the number of valves and the excessive number of valves at the outlet of the diverter was not conducive to the development of streamwise vortex. The overall radiation intensity of the mixed duct gradually decreased with the increase of the forced cooling airflow flow rate. When the ratio of the cooling airflow flow rate to the main flow rate was 0.1, the overall radiation intensity decreased by a peak of 68.3% compared with the situation without cooling airflow.

Using a particle deposition model and a dynamic mesh technique, the deposition characteristics over a flat plate surface with film cooling under different mass flow ratios and particle sizes were studied. In addition, the effects of particle deposition on film cooling over the flat plate were investigated. Results revealed that at a low particle velocity, the blowing of the coolant acting on the particles made it difficult to deposit in the downstream region of film holes, and an obvious ridged shape of deposits was formed on both sides due to the blocking and entrainment of the cooling jet. However, distribution of the capture efficiency presented a bimodal pattern with the change of particle sizes. At high mass flow ratios, the ridged deposition significantly improved the cooling effectiveness, which was 6.15% higher than that before deposition. Additionally, particle deposition could enhance the lateral spreading of the coolant and improved the laterally-averaged cooling effectiveness. In general, the effects of particle deposition on film cooling performance were determined by both distribution characteristics and thickness of the deposition.

Excessive high intake temperature is one of the key problems limiting the performance of aero-engines, mass injection and pre-compressor cooling (MIPCC) technology can effectively reduce the intake temperature of aero-engine. In order to investigate the influence of MIPCC technology on the temperature field in the inlet, a mathematical model of the droplet atomization and evaporation process was established. Based on Euler-Lagrange method, the mathematical model was used to realize the two-way coupling of the gas-liquid two-phase and describe the MIPCC process in the intake port of an aero-engine. Compared with the existing test results, the accuracy of the mathematical model was verified. The effects of water-air ratio, injection velocity, particle diameter and nozzle cone angle on the cooling effect and temperature distribution of the inlet were studied by using the mathematical model. The results showed that when the water-air ratio increased from 0.02 to 0.055, the cooling ratio increased from 8.10% to 19.87%, and the evaporation rate decreased from 85.76% to 79.80%; when the water-air ratio was 0.055, the injection velocity was 10 m/s, the droplet size was 25 μm and the nozzle cone angle was 15°, the maximum temperature drop coefficient was 22.77%. Increasing the nozzle cone angle and decreasing the injection velocity made the temperature field distribution in the outlet section of the inlet more uniform.

The oxidation characteristics of RP-3 kerosene/O₂ were experimentally tested in the flow reactor under the conditions of the equivalence ratios of 0.5, 1.0 and 2.0, the temperature range of 550−1200 K, the pressure of 0.1, 3.0 MPa. The results showed that, with the increase of equivalent ratio from 0.5 to 2.0, the starting temperature of each species formation and the corresponding temperature of the peak mole fraction of each species increased. With the increase of pressure from 0.1 MPa to 3.0 MPa, the starting temperature of each species formation and the corresponding temperature of the peak mole fraction of each species decreased, and the peak mole fraction of alkanes increased while that of alkenes decreased. Meanwhile, the ignition delay characteristics of RP-3 kerosene/O₂ were experimentally tested in the shock tube under the conditions of the equivalent ratios of 0.8, and 3.5, the pressure of 0.2, 1.0, and 5.0 MPa, the temperature range of 950−1500 K. The results showed that, with the increase of the pressure and temperature or the decrease of equivalent ratio from 3.5 to 0.8, the ignition delay time of RP-3 kerosene/O₂ was shortened.

For continuous fiber reinforced composites turbo-shaft structural damage evolution and failure mechanism analysis, based on the macro-mechanics and meso-mechanics analysis method of cross-scale, a finite element simulation model with the same size of the shaft structure verification model and a micro-mechanics representative volume element (RVE) model was established. The damage evolution of shaft structure was predicted and its failure mechanism was analyzed. Under reverse torque, the damage of [45]₆ shaft structure structure began with interface cracking, the cracks were extended to both sides of titanium alloy, and the shear deformation of titanium alloy finally drove the fiber fracture. Under forward torque, the damage of [45]₁₀ shaft structure began with matrix damage, titanium alloys on both sides of the fracture were pressed against each other, and finally the fiber was cut. The failure mode verification experiment of composite shaft structure was carried out, different failure modes in the failure process were identified by acoustic emission and scanning electron microscopy techniques. The simulation results were compared with experiment results to verify the validity of the model and method. The damage evolution process and failure mechanism of the turbo-shaft structure under torsional load were simulated and the failure strength was predicted. The damage evolution process and failure mechanism of turbo-shaft structure under torsional load were simulated and the failure strength was predicted. The results showed that the torsional strength was the lowest when the layer was laid at 0° and 90°, and the highest when the layer was laid at 45°, which increased nearly three times. The prediction model and analysis conclusions could provide a basis for the design and application of fiber reinforced composites.

For the problem that rolling bearing diagnosis is affected by the environmental noise so that extraction of characteristic frequency is difficult, a rolling bearing fault diagnosis method based on wavelet packet transform and complete ensemble empirical model decomposition adaptive noise (CEEMDAN) was proposed. The raw vibration signal collected by the sensor was split through CEEMDAN and the high-noise signal and low-noise signal were divided through the kurtosis-correlation coefficient screening criteria (K-C). The wavelet packet transform was used to split the high noise signal and then select appropriate component reconstruction to filter out the environmental noise and integrate with the low noise signal to generate a new vibration signal for envelope demodulation, and the actual fault characteristic frequency was extracted to achieve fault diagnosis of rolling bearings. After comparative experiments, the method proposed clearly extracted the rotational frequency, fault characteristic frequency and its frequency multiplier and modulation frequency of rolling bearings, and the signal-noise ratio after noise reduction was increased by 7.61 dB from the simulation signal calculation, which effectively optimized the effect of noise filtering.

Continuous erosion test was carried out for the CCF300/QY9511 carbon fiber/ bismaleimide resin composite laminate, and the mass erosion rate and damage law under different erosion conditions were studied. It was found that the mass erosion first increased and then decreased with the increase of the erosion angle. The peak erosion rate appeared around the erosion angle of 60°. The erosion rate increased with the increase of the erosion rate, while it first increased and then decreased with the increase of the sand supply rate. Laying plain weave cloth on the surface of the composite laminates could enhance the ability of the composite material to resist low-speed erosion. However, the improvement effect under high-speed erosion was not obvious. The main erosion mechanisms of composite materials accounted for the generation of micro-cracks, fiber breakage, fiber-matrix debonding, and matrix deformation. The research clarified the removal mechanism and damage change law of composite laminates, laying a foundation for subsequent research on erosion resistance of composite materials.

In order to solve the structural design problem of missile seeker with high temperature and high loads, a multi-scale topology optimization design method was introduced to optimize the missile seeker. A multi-scale parallel topology optimization method for thermo-mechanical coupled continuum structures under steady-state heat source was proposed. With this method, the equivalent thermal load introduced by heat source was coupled to the force load on the macroscopic scale, and the macroscopic configuration distribution consistent with the thermo-mechanical coupled load was obtained. At the micro scale, the clustering method was used to classify microstructures to improve the computational efficiency and solve the problem of scale separation in macro and micro structures. A multi-scale parallel topology optimization model based on solid isotropic material with penalization model was established with the structural flexibility as the objective function and the volume fraction of materials as the constraint. The sensitivity was analyzed and calculated by the direct method under the thermodynamic coupling condition, and the design variables were optimized by the OC criterion method. Hence, the effective macro- and micro-scales parallel topology optimization model was obtained with thermo-mechanical coupled loads. The proposed method was validated by optimizing a cantilever beam structure and the results showed that the designed structure not only had the load-bearing capacity under thermo-mechanical coupling loads, but also had a certain degree of thermal protection ability. At last, the proposed method was applied for performing the integrated design of the missile seeker structure under the force-thermal coupling condition. A good structure of the missile seeker with both load-bearing performance and thermal insulation performance was designed. The two cases demonstrated that the ideal optimized structures were achieved while ensuring 50% mass reduction. Therefore, this has provided a feasible method for structure integrated design under the force-thermal coupling condition, showing that the present method is rational and valuable in engineering application.

In order to reveal the dynamic response characteristics of the rotor system during shutdown after aero-engine blade loss, considering the blade disk moment of inertia asymmetry and the characteristics of variable speed during shutdown, the transient dynamic response analysis model of asymmetric variable speed rotor was established to analyze the transient response of rotor system during shutdown after blade loss. The results showed that when the blade was lost and the rotor passed through the resonance zone, the transient vibration response of the rotor system was intensified, accompanied by transverse natural vibration. When the asymmetric ratio of moment of inertia was 0.2, the peak response of the rotor system differed by 58% without considering the asymmetry of the disk. Therefore, for the loss of large mass blades or multiple blades, the moment of inertia asymmetry can’t be ignored, showing that the established rotor dynamics model can effectively analyze the complex vibration response characteristics of large asymmetric rotor during shutdown.

According to the performance evaluation and optimization research requirements of counter-rotating propellers aerodynamic and aerodynamic noise, a high power counter-rotating propellers dynamic simulation test rig was developed based on acoustic wind tunnel, and the data processing method of counter-rotating propellers wind tunnel test was developed. The counter-rotating propellers dynamic simulation test rig was powered by 300 kW electric motor, accelerated by the gear box to realize internal and external drive shaft reverse rotation, and the aerodynamic was measured by rotating shaft balances. After development of the rig, aerodynamic and aerodynamic noise test of counter-rotating propellers were carried out in 5.5 m×4 m acoustic wind tunnel. The result showed that the rotating speed control accuracy of counter-rotating propellers dynamic simulation test rig was better than 0.5 r/min, the transmission efficiency reached 97.7%, and the test rig operated stably and reliably. The test repeatability accuracy of counter-rotating propellers pull coefficient was better than 0.002 1, that of counter-rotating propellers power coefficient was better than 0.002 2, and that of counter-rotating propellers aerodynamic noise was better than 0.5 dB.

In order to reduce aerodynamic and thermal loads of the supersonic vehicle, a combination model of aerospike/aerodisk and double jet was studied, and the effects of geometrical parameters and jet parameters on flow field characteristics, drag and heat flux reduction were analyzed numerically. The results showed that: the length-to-diameter ratio of the aerospike had little effect on the drag reduction efficiency of the configuration, but had a great effect on the heat flux reduction efficiency. When the diameter ratio of the aerodisk increased, the drag reduction efficiency of the configuration increased first and then decreased, and the heat flux reduction efficiency decreased first and then increased. However, when the total pressure of the opposing jet was high, the diameter ratio of aerodisk had little effect on the drag and heat flux reduction efficiency. When the total pressure ratio of the opposing jet increased, the drag and heat flux reduction efficiency of the configuration was kept at a high level, and the variation range was not obvious. When the total pressure ratio of the lateral jet increased, both the drag and heat flux reduction efficiency of the configuration increased, and the change rate of the drag reduction efficiency increased, while the change rate of the heat flux reduction efficiency decreased. The location of the lateral jet was far away from the blunt body, which increased the drag reduction efficiency and decreased the heat flux reduction efficiency. The drag reduction efficiency of 57.1% and heat flux reduction efficiency of 100.4% can be achieved by properly selecting the aerospike/aerodisk and double jet parameters.

An optimization approach based on free-form deformation technology and genetic algorithm was proposed for the shape optimization of two-dimensional transverse groove for drag reduction. The triangle was employed as the origin groove section, which was geometrically parameterized based on free-form deformation. The minimum groove drag force calculated by flow field simulation was used as optimization goal, while the genetic algorithm was adopted as the optimization method. The optimization results illustrated that the drag reduction rate of the optimized groove was improved from 6.4% to 10.1% at 0.8 Mach, compared with the origin triangular groove. The optimization approach indicated that the free-form deformation method and genetic algorithm can expand the design space for shape optimization of the drag reduction groove. The present work demonstrates a new approach for shape optimization of groove.

In view of the problem that the current theory can not accurately calculate the meshing impact time of loaded gear, a calculation method of meshing impact excitation of loaded gear pair based on cylindrical collision theory and contact dynamics theory was proposed to accurately calculate the meshing impact time and impact force of loaded gear. The mathematical model of meshing impact of involute gear under load and deformation was established. The exact position of the outer meshing point of the line was calculated by the inversion method, and the meshing impact force of the tooth pair was obtained based on the cylindrical collision theory. At the same time, on the basis of the established mathematical model of meshing impact, the impact time was accurately calculated and compared with the existing calculation methods. Then, according to the actual working condition of the gear, the dynamic contact finite element analysis of the gear pair of the aircraft gearbox was carried out, while the impact time and impact force were extracted, and compared with the theory. The results showed that the error of the meshing impact time of the calculation model was within 15%, and the error of the maximum meshing impact force was less than 10%. Therefore, the impact excitation calculation method can accurately and quickly solve the impact time and the maximum meshing impact force.

To solve the problem of high temperature failure of cylindrical roller bearing under high-speed operation, volume of fluid (VOF) method and multiple reference frame (MRF) model were used to model the oil supply groove and bearing cavity of cylindrical roller bearing inner ring, respectively, the oil supply situation of the oil supply groove was calculated and the result was applied to the bearing cavity model. The temperature rise of the oil inlet hole under the ring relative to the roller was calculated, and the final temperature rise in the bearing cavity was obtained by weighted average. The effects of bearing speed and oil supply rate on the temperature rise of friction in bearing chamber and the temperature rise of lubricating oil viscous shear were analyzed. The results showed that when the oil supply rate of the bearing was constant, the higher rotational speed indicated all the increase in the friction of the internal components of the bearing, the viscous shear force of the lubricating oil in the cavity and the friction and viscous temperature rise. When the bearing speed was constant, the increase of lubricating oil viscosity shear temperature rise and the improvement of cooling effect caused by the increase of oil content were higher than the latter when the oil content was low, and then these two were gradually flat. The viscosity temperature rise first decreased and then stayed at a certain level, while the friction temperature rise decreased. This study can provide a reference for lubrication design of high-speed cylindrical roller bearing ring.

In order to optimize curvic couplings assembly process, the influence of machining deviation of curvic couplings tooth surface on fitting state was theoretically studied. Based on the curvic coupling machining theory, the effect of key machining parameters on surface deviation was investigated. An assembly initial tooth surface clearance model of the curvic couplings was built. The effect of surface deviation on assembly initial tooth surface clearance of the curvic couplings was analyzed. According to theoretical and experimental study, tooth surface deviation directly caused the assembly initial tooth surface clearance. By optimizing the installation phase, the mean and variance of assembly initial tooth surface clearance can be reduced by 18%, and the variance can be reduced by 25%. The work provides a foundation for the principle of the assembly accuracy formation and parameter optimization of curvic couplings, contributing to assembly quality improvement of aero-engine rotors connected by curvic couplings.

To improve the optimization design quality of axial compressor airfoil, the parametric modeling method based on superimposing thickness on suction surface was proposed. The compressor airfoil optimization platform based on Kriging surrogate model and Differential Evolution algorithms was developed, and the control parameters of the suction surface were used as optimization variables to optimize the performance of transonic and supersonic airfoils. The results showed that the parametric modeling method based on superposing thickness distribution on suction surface can express the airfoil well and was successfully applied to the optimization design platform. The loss of optimized transonic and supersonic airfoils at design condition decreased by 10.66 % and 7.4%, respectively. The analysis showed that as for the main characteristics of optimized transonic airfoil, the curvature of the profile near the leading edge of suction surface decreased, and the shock wave intensity decreased. Therefore, the shock wave loss and boundary layer loss decreased, the load at the middle and rear positions increased and the expansion capacity of the expansion channel increased. The optimization of supersonic airfoil should consider the profile of suction surface within the aft expansion passage additionally, because of more significant boundary layer influence. The position and width of throat can affect the chocking incidence angle.

In order to investigate the influence law and mechanism of the relative circumferential position of the intake struts and downstream blades on the excitation and vibration of the rotor blade, the first 1.5 stage of a heavy-duty gas turbine compressor with intake struts was numerically simulated. Through analysis of the flow field and vibration of the rotor blade, it was found that the circumferential position of the intake struts had little effect on the total pressure ratio and total temperature ratio, but it could obviously change the excitation and vibration level of the rotor blade. When intake strut wakes and guide vane wakes coincided, the two wakes were superimposed and strengthened, resulting in the overall enhancement of excitation and vibration on the rotor blade. The circumferential position of struts obviously changed the combined effect of strut wake and downstream static blade potential flow on rotor blades, which had obvious influence on the unsteady load and global vibration in the middle chord length, but had little influence on the unsteady load near the leading edge and trailing edge. The research results can provide a reference and guidance for the installation of struts.

The spray characteristics of gas-centered swirl coaxial injectors in three structures of the gas injector, namely, the smooth inner wall (A), inner wall with concave cavities (B), and inner wall with projections (C), were examined by experiments. At the same time, in order to analyze the change of flow field caused by the change of the inner wall structures of the gas injectors, the pure gas flow field was simulated without considering the liquid phase. The results demonstrated that the spray angles of the three injectors increased with the gas mass flow rate, but decreased with the liquid mass flow rate. Adding a concave cavity to the inner wall of gas injector had little effect on spray angle, breakup length and self-pulsation frequency of the injector. But inner wall with projections of gas injector had a significant effect on spray characteristics. Under the same working conditions, the inner wall with projections could enhance the ejection effect of the gas injector outlet, decrease the spray angle, and the stronger gas-liquid interaction could reduce the breakup length. When the self-pulsation occurred, the inner wall with projections also increased the frequency of self-pulsation. The self-pulsation frequency of the three injectors increased with gas mass flow rate, and the induction and maintenance mechanisms of the self-pulsation of the three injectors were analyzed. The effects of different concave cavity sizes and projection sizes on spray characteristics were investigated through experiments. For injector B, the spray angle, breakup length and self-pulsation of the spray were almost the same. The spray angle and breakup length of injector C were smaller than those of injector B, and decreased with the size of projection, while the self-pulsation frequency was larger than that of injector B, and increased with the size of projection.