Unsteady three-dimensional icing numerical-simulation method

A numerical simulation and non-steady-state technology, applied in electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as large errors in clear ice and mixed ice

Inactive Publication Date: 2018-08-28
NORTHWESTERN POLYTECHNICAL UNIV
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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,

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Embodiment Construction

[0032] The specific embodiment of the present invention is described below:

[0033] The unsteady three-dimensional icing calculation method proposed by the present invention consists of an inner loop and an outer loop. Firstly, on the icing surface, a group of stagnant units is selected according to the included angle between the impact direction of the water droplet and the normal direction of the calculation unit. Starting from these stagnation units (initial calculation unit), the mass conservation and energy conservation are used for each net Carry out icing thermodynamic calculations on the cell to obtain the icing amount and overflow water amount of the current cell. Determine the flow direction and flow rate of the overflow water according to the flow direction of the air in the current grid unit, and mark the grid units to be calculated in the next cycle and the inflow water volume of each grid unit, such as figure 1 In the inner loop, when the inner loop is complete...

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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...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/15G06F30/20
Inventor 张丽芬刘振侠胡剑平吕亚国刘振刚
Owner NORTHWESTERN POLYTECHNICAL UNIV
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