Unsteady three-dimensional icing numerical-simulation method

Abstract

The invention discloses an unsteady three-dimensional icing numerical-simulation method, and belongs to the field of aircraft flight safety design. An N-S equation is used for calculating an air field, a Lagrangian method is used for calculating movement trajectory of water droplets, icing quantity and overflow water quantity are calculated according to mass conservation and energy conservation, aflowing direction of overflow water and flow distribution of different directions are calculated and obtained by a velocity vector of local air and position vectors of a current unit and adjacent units. By using the unsteady calculation method, icing calculation starts from a stagnation unit group in each time step, thermodynamic equilibrium calculation is carried out for each grid unit therein,the icing quantity, the overflow water quantity and the number of a next grid unit to which the overflow water flows are obtained, calculation advances backwards according to the flow direction of theoverflow water until all the grid units on an icing surface are traversed, and then calculation of a next time step is entered. Through comparison of a calculation example and the prior art, it is proved that the unsteady three-dimensional icing numerical-simulation method provided by the invention is effective.

Description

technical field [0001] The invention relates to the technical field of aircraft flight safety design, in particular to an unsteady three-dimensional icing numerical simulation method. Background technique [0002] Icing seriously threatens the flight safety of aircraft. There are two ways to study the icing problem: experiment and calculation. The cost and operating cost of the ice wind tunnel used in the icing experiment are high, and the ice wind tunnels currently in use in my country are all small ice wind tunnels, limited by their size, some working conditions cannot be tested, so the experimental method is used to study There are many difficulties and obstacles in the icing problem. With the development of numerical calculation methods and computer technology, numerical simulation has increasingly become an important means of icing research. Numerical simulation can conduct qualitative or quantitative analysis on the researched problems at a lower cost and faster spee...

AI Technical Summary

Problems solved by technology

Numerical simulations of icing in China have gradually increased in recent years. Two-dimensional icing calculation research has been carried out more comprehensively, and three-dimensional icing calculations have also been gradually developed. There are three significant difficulties in three-dimensional icing calculations: the determination of stagnation units, Water flow direction and icy surface mesh traversal

In addition, the current three-dimensional icing calculation is carried out according to the quasi-steady method, and the icing process is often regarded as a time step, which is somewhat different from the real icing process, resulting in large errors between the calculation results of clear ice and mixed ice.

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