7 results about "Advance ratio" patented technology

The invention relates to the technical field of icing wind tunnel tests, in particular to a propeller icing wind tunnel test working condition similarity matching method and a storage medium. A first calculation model is established based on a forward ratio similarity criterion of a propeller and a first similarity criterion, and a second calculation model is established based on a plurality of set similarity criteria. Then, basic parameters of the target propeller are obtained, and the basic parameters comprise the size of the target propeller, the first angular speed, the first incoming flow wind speed and the scaling ratio of the icing wind tunnel test on the target propeller; and inputting the first angular velocity and the scaling proportion into a first calculation model to obtain a scaled second angular velocity. And finally, inputting the basic parameters and the second angular velocity into a second calculation model to obtain test working condition parameters of the target propeller in the icing wind tunnel test. Therefore, the design period of similar matching of the propeller icing wind tunnel test working conditions is shortened, and the quality of the scaled test working condition data is ensured.

Systems and methods for controlling a variable-pitch propeller of an aircraft are provided. A method for controlling the variable-pitch propeller includes using a feedback controller, operating the variable-pitch propeller at a current operating condition including a current rotational speed, determining a speed error between the current rotational speed of the variable-pitch propeller and a set point rotational speed for the variable-pitch propeller, determining a gain for the feedback controller based on a power coefficient and an advance ratio of the variable-pitch propeller. Using the feedback controller, a propeller pitch command is determined based on the speed error and using the gain. The pitch of the variable-pitch propeller is adjusted according to the propeller pitch command to reduce the speed error.

Propulsion devices that provide increased propeller efficiency when operating outside of an optimal advance ratio are described. In one example, a propulsion device includes a hub having a curved surface extending around and along a rotation axis of the hub. The propulsion device can further include two or more rows of blades extending radially outward from the curved surface and including a first row of blades having a first blade and a second row of blades having a second blade that is angularly and axially offset from the first blade on the curved surface. A first centerline of the first blade and a second centerline of the second blade each intersect with a helical line that extends along the rotation axis of the hub. The first blade and the second blade collectively form a helical pattern of blades that projects radially outward from the curved surface along the helical line.

The application relates to the technical field of ice wind tunnel test, in particular to a method for matching test working conditions of a propeller ice wind tunnel test and a storage medium. A first calculation model is established based on a forward ratio similarity criterion and a first similarity criterion of the propeller, and a second calculation model is established based on a plurality of set similarity criteria. Then, the basic parameters of a target propeller are acquired, the basic parameters comprising the size, a first angular velocity and a first incoming flow wind speed of the target propeller, and a scale reduction ratio of the target propeller for the ice wind tunnel test. The first angular velocity and the scale reduction ratio are input into the first calculation model to obtain a second angular velocity after scale reduction. Finally, the basic parameters and the second angular velocity are input into the second calculation model to obtain test working condition parameters of the target propeller for the ice wind tunnel test. In this way, the design cycle of matching the test working conditions of the propeller ice wind tunnel test is shortened, and the quality of the test working condition data after scale reduction is ensured.

This invention relates to an aerodynamic optimization design method for propellers of multi-condition unmanned aerial vehicles (UAVs), and more particularly to an optimization design method for propellers of low Reynolds number and small advance ratio UAVs based on genetic algorithms and sheet theory. It belongs to the field of aerodynamic performance technology for micro fixed-wing UAVs. The method optimizes the thrust coefficient, hovering and cruise efficiency of the propellers of UAVs with low Reynolds number and small advance ratio under hovering and cruise conditions. The chord length and twist angle of the corresponding propeller blades are obtained through the optimized thrust coefficient, hovering and cruise efficiency, and the UAV propeller configuration is designed based on the chord length and twist angle of the propeller blades.

The application provides a high-speed high advance ratio rotor transient dynamics analysis method, the method comprises the following steps: establishing a variable speed transient process dynamics equation, wherein the variable speed transient process dynamics equation comprises a system kinetic energy term; two coordinate systems are established, and the system kinetic energy term is derived based on the coordinate systems to obtain a system kinetic energy equation; a transient aeroelastic analysis model is established based on the system kinetic energy equation; variable speed transient dynamics analysis is carried out based on the transient aeroelastic analysis model to obtain transient aeroelastic response results; meanwhile, the application also provides a high-speed high advance ratio rotor transient dynamics analysis device; the application develops a high-speed high advance ratio rotor transient dynamics calculation method, studies the transient aeroelastic behavior characteristics in the variable speed process, and provides a theoretical basis and technical support for the development of high-speed high advance ratio rotors.

This application discloses a method, apparatus, device, and medium for calculating the performance of a propeller under negative advance conditions. The method includes: acquiring the incoming flow velocity, target values ​​of the axial induced velocity coefficient at the propeller disk, and target values ​​of the circumferential induced velocity coefficient at the propeller disk, wherein the target propeller is in a negative advance state; determining the target value of the actual airflow velocity angle of the target propeller based on the incoming flow velocity, the target values ​​of the axial induced velocity coefficient at the propeller disk, and the target values ​​of the circumferential induced velocity coefficient at the propeller disk; determining the blade element parameters of the target propeller based on the target value of the actual airflow velocity angle and the drag angle of the blade element of the target propeller; and determining the values ​​of the performance parameters of the target propeller based on the blade element parameters, the total number of blades of the target propeller, and the propeller radius. This application embodiment can accurately calculate the propeller performance under negative advance conditions based on target values ​​applicable to negative advance conditions.