Overview of the simulation technology of aero engine paddle-engine matching test

A mature aviation piston aircraft engine needs to perform better power output performance within the flight envelope. In addition to the power output characteristics of the engine, it is also necessary to understand the power absorption characteristics of the propeller, and based on the external characteristic curve of the engine and the propeller propulsion characteristic curve of the propeller, an optimal method for the piston engine to match the propeller is derived. Understanding the experimental and simulation technologies related to paddle hair matching will help the research and promotion of paddle hair matching.

Aviation propeller performance test technology

After the propeller is designed, the propeller performance test and propeller matching test are required. Through the propeller performance test, the propeller's tensile force, torque and power data can be obtained at different speeds, and the characteristics of the propeller can be preliminary understood. Through the propeller matching test, the overall performance of the propeller and the engine can be evaluated to achieve an optimal power matching.

The power drive device for the propeller performance test can be an engine or a motor. The rotation speed of the propeller is controlled, and the tension and torque of the propeller at each speed is measured through the tension sensor and the torque sensor.

The power matching test of propeller and engine is to install the propeller on the engine to be matched and to measure the performance data of the propeller in a static ground, empty platform or wind tunnel. The goal of propeller matching is to enable the propeller to perform a greater propeller effect under the usual operating conditions of the aircraft, and low fuel consumption should be considered during cruising. If the distance paddle matches, it is necessary to consider whether the working environment of the paddle is empty or low, which is mainly used for take-off and climbing state or cruise state to avoid the propeller being too heavy or too light under common working conditions. For propellers used for empty operations, in the absence of empty tables and wind tunnel test conditions, the matching calculations at corresponding ratios and speeds need to be carried out based on the aerodynamic characteristic data such as propeller power coefficient, thrust coefficient, inlet ratio, efficiency, etc.

Aviation propeller simulation technology

The three-dimensional simulation technology of aviation propellers mainly includes pneumatic fluid simulation (CFD), structural simulation (CAE), fluid-solid coupling simulation.CFDComplex nonlinear flow can be simulated, and various factors affecting the efficiency of the propeller can be considered on multiple sides. By analyzing and calculating the flow field around the propeller, the aerodynamic characteristic data of the propeller can be obtained.

The propeller blades will deform under the action of pneumatic and centrifugal forces. In addition, the pressure pulsation of the air and the engine output shaft will cause the propeller to vibrate. In the design of propeller, it is necessary to not only analyze its strength, but also understand its dynamic characteristics, especially the blades.-Paddle Hub-Power characteristics of paddle shaft coupling.CAEIts mode can be solved and its vibration frequency response under the same excitation conditions can be analyzed. The application of composite materials on paddles greatly improves the specific strength and stiffness of the paddles, but the anisotropy of composite materials makes the research on its mechanical properties much more complicated than that of metal paddles, and needs to be used.CAETo study the relationship between blade fiber laying and strength and the failure process of composite materials.

The simulation of propeller blades also requires consideration of flow-solid coupling. The aerodynamics of the propeller flow field affect the deformation of the blade structure, and the deformation of the blade will in turn cause changes in the air flow field to act repeatedly to form a coupling effect between two different physical fields. Establish CFD/CSD The coupling method has become the focus of the research on numerical simulation of propellers.

Summarize

The non-aerospace test simulation technology of piston engines has been very complete. It only requires appropriate focus and optimization based on existing mature technologies and the application characteristics of aero engines. The components of propellers are simpler than those of piston engines, but the composite properties of their materials and the variability of their motion characteristics make simulation analysis more difficult. Using advanced simulation technology to carry out fast paddle matching analysis will be our focus in the future.