10 results about "Gas dynamics" patented technology

The invention relates to the technical field of aerospace engines, in particular to an axial expansion combustion chamber and a rotary detonation engine, which comprise a base, a gas distribution assembly and an axial expansion combustion chamber which are coaxially and sequentially arranged along the axial direction, the axial expansion combustion chamber is improved aiming at the technical defect that the flow speed of supersonic airflow in an existing uniform-section combustion chamber is reduced due to the gas dynamic effect and the wall surface heat sink effect, so that the inner wall of the axial expansion combustion chamber expands outwards in the axial direction of the airflow; therefore, the sectional area of an inner channel of the axial expansion combustion chamber is gradually expanded in the axial direction, and an expansion type flow channel is formed. Compared with the prior art, the inner channel has the beneficial effects that through the physical geometric structure change of axial expansion of the inner channel, the total pressure loss and speed attenuation of airflow in the flowing process are successfully compensated, the energy release efficiency in the combustion chamber is remarkably improved, and the self-sustaining capacity of an engine in the combustion process is effectively enhanced.

The application belongs to the technical field of aero-engines, and particularly relates to a method for evaluating a Mach number and total static pressure at an inlet of a main combustion chamber, comprising the following steps: S1: arranging a test rake at a windward surface of a support plate of a pre-expander of the main combustion chamber, and measuring and obtaining total pressure P31 and total temperature T31 of a support plate section; S2: obtaining known physical parameters of an outlet section of a high-pressure compressor, including a flow area A3 and an air mass flow W3 at the inlet of the main combustion chamber; S3: based on the total pressure P31 and the total temperature T31 of the support plate section and the parameters A3 and W3 of the outlet section of the compressor, a Mach number Ma3 of the outlet section of the compressor is obtained by iteratively solving a gas dynamics relationship; and S4: based on the obtained Mach number Ma3, total pressure P3 and static pressure Ps3 of the outlet section of the compressor are calculated.

This invention discloses a semi-analytical method and system for calculating the stiffness and damping coefficients of foil gas dynamic bearings, relating to the field of air conditioning and clothing temperature control technology. It aims to address the shortcomings of traditional Reynolds equation methods in terms of accuracy and universality, as well as the low computational efficiency and mesh distortion issues of existing CFD methods. The method includes: constructing a fluid-structure interaction (FSI) computational model to calculate and obtain the static equilibrium position of the journal; applying an eccentricity perturbation at the static equilibrium position and performing an additional steady-state FSI calculation to obtain the four stiffness coefficients of the foil bearing using a first set of analytical formulas; applying small-amplitude simple harmonic vibrations along the x and y directions to the journal and performing two transient FSI calculations to obtain the four damping coefficients of the foil bearing using a second set of analytical formulas. This invention combines high accuracy and high computational efficiency, providing an efficient and reliable analytical tool for evaluating the dynamic characteristics of foil bearings and designing the stability of the rotor systems they support.

The invention provides a method and a system for constructing a thermal hydroelastic equivalent model, and the method comprises the steps: obtaining the structural dynamic characteristics of a real aircraft in a target thermal environment through thermal-fluid-solid multi-physics field coupling simulation, and taking the structural dynamic characteristics as a target value of equivalent design; decoupling the aerodynamic thermal environment influence represented by the target value, and equivalently converting the aerodynamic thermal environment influence into design requirements for physical attributes of an equivalent model at normal temperature; based on the design requirements, an equivalent model with the structural dynamic characteristics matched with the target value under the normal temperature condition is designed through inversion of an optimization method. According to the design method of the thermodynamic elasticity model of the equivalent temperature effect, the influence of the temperature on the structure is equivalent to weakening of the structural strength, and related research on the thermodynamic elasticity can be carried out in a conventional hypersonic wind tunnel.

The application provides an air suspension fan predictive maintenance method and system based on digital twinning, comprising: collecting airflow mutation characteristics when high-temperature dust-containing waste gas rushes into the air suspension fan, transmitting to a digital twinning system, and determining the airflow mutation characteristics; extracting a foil and bearing local gap narrowing trend from a foil non-uniform expansion amount, calculating a spatial distribution after the gap is narrowed, and obtaining a target gas film thickness value; comparing the target gas film thickness value with a preset collision and grinding threshold value, if the target gas film thickness value is less than the threshold value, then evaluating a collision and grinding risk probability through a Monte Carlo method; if the collision and grinding risk probability exceeds a preset safety range, then calculating a gas film stiffness fluctuation range based on a gas dynamics theory; and extracting vibration amplitude analysis results from air suspension fan foil bearing dynamic response parameters, and calculating a stability prediction index.

The invention provides a gas flow control method and system applied to a solid-state working medium electric propulsion system, and the method comprises the steps: firstly constructing a second-order nonlinear prediction model from heating power to output flow in order to solve the problems of strong nonlinearity, multivariable coupling and strict safety constraints in a solid-state iodine sublimation process; the model accurately depicts a complete physical process of heating sheet thermal inertia, contact thermal resistance, iodine phase change dynamics and pipeline gas dynamics. And on the basis, rolling optimization is executed in each control cycle: a future flow trajectory is predicted based on a current state and a model, and an optimization problem with constraints is solved online to obtain an optimal heating power sequence. According to the method, high-precision and overshoot-free tracking of the flow is achieved, it is strictly guaranteed that the system operates within safety constraints, and the performance and reliability of the solid-state electric propulsion system are remarkably improved.

The invention relates to the technical field of pneumatic turbines, in particular to a rotating wheel for a pneumatic turbine, and solves the problem that an existing rotating wheel of the pneumatic turbine is low in efficiency. The rotating wheel comprises a rotating wheel hub, a rotating wheel outer ring and a plurality of wing-shaped blades, and the wing-shaped blades are connected between the hub and the outer ring to form a divergent blade runner; the wing-shaped paddle is in a three-dimensional twisted wing shape, and the wing inner side and the wing outer side of the wing-shaped paddle have different relative thicknesses, relative cambers and mounting angles; sub-runners are formed between the adjacent paddles, the cross sectional areas of the sub-runners are gradually reduced from an inlet to an outlet, and the airflow directions of the inlet and the outlet are configured to be axially parallel or basically parallel to the rotating wheel. The rotating wheel can be used in multi-stage series connection, and parameters of each stage of blade are gradually changed and optimized in the airflow direction. Through the collaborative design of the divergent flow channel and the three-dimensional twisted blades, the full-flow-channel airflow organization is optimized, the energy conversion efficiency is remarkably improved, the overall efficiency up to 89.8% is achieved in a four-stage pneumatic turbine, and the structural universality is high.

This invention relates to the field of helicopter and rotorcraft unmanned aerial vehicle (UAV) technology, specifically to a method for estimating the jet thrust of a jet rotor, comprising: obtaining first temperature and pressure parameters of the aero-engine outlet gas based on the characteristic parameters of the compressor, combustion chamber, and turbine of the aero-engine; calculating heat transfer losses based on the heat transfer area, geometric parameters, and temperature parameters of the main shaft duct; obtaining second temperature and pressure parameters of the outlet gas of the main shaft duct based on the heat transfer losses and the pressure loss at the first bend; dividing the rotor duct into multiple segments and calculating the intra-segment losses in each segment; obtaining third temperature and pressure parameters of the gas before the nozzle based on the pressure loss at the second bend; and inputting the optimal nozzle cross-section, the third temperature, and the pressure parameters into a gas dynamics model for processing to obtain the jet thrust. This invention can improve the accuracy of jet thrust calculation for jet rotors.

The application discloses a kind of hypersonic vehicle global active thermal protection methods, it is related to hypersonic vehicle thermal protection field.Gas dynamic heat peak value is greater than given threshold value, jet port opens, cooling working medium is injected flow field from jet port along the free flow reverse direction, and forms backflow area and covers in aircraft head, realizes head area thermal protection;Cooling working medium reconfigures the shock wave of coming flow, makes the arc shock wave of aircraft head become conical shock wave, and forms reattachment shock wave in aircraft shoulder area;Magnet is installed in aircraft inner wall surface, generates magnetic field and acts on plasma in flow field and generates external thrust force, pushes reattachment shock wave away from wall surface, guides cooling working medium to downstream, realizes global thermal protection.The effect and benefit of the application are: cooling working medium demand is small, thermal protection area coverage area is large, does not change aircraft shape structure, and reliability is high.

The invention discloses an accelerated analysis method for aerodynamic characteristics of a free molecular flow of an aircraft, belongs to the field of numerical simulation of rarefied gas dynamics, and aims to solve the problem of low shadow analysis calculation efficiency of a ray tracing surface element method in aerodynamic analysis of an extremely low earth orbit aircraft. The method comprises the following steps of: initializing parameters and reading a surface grid; establishing a uniform background grid as a spatial index, and quickly associating surface triangular surface elements to corresponding sub-grids; an OpenMP parallel instruction is adopted, and ray tracing-based shielding judgment is executed on a large number of surface elements at the same time; and calculating the aerodynamic contribution of the unshielded surface element according to the free molecular flow theory, and integrating to obtain the overall aerodynamic force. According to the method, the calculation complexity of shadow analysis is remarkably reduced from O (N) through cooperation of spatial index and parallel calculation, and efficient and high-precision prediction of the aerodynamic characteristics of the extremely-low-orbit aircraft is achieved on the premise that precision is guaranteed.