Ivanov

A mathematical model of the liquid flow in heterogeneous systems is developed. Heterogeneous systems consist of a porous body with the pore size from 20 nm to 360 nm and a lyophobic (non-wetting) liquid. The paper represents theoretical basics to describe a hysteresis of liquid filling and outflow processes from the pores under the pressure gradient, and also with no liquid outflow after reducing a pressure in the system to the atmospheric value under static and dynamic loads. The paper presents experimentally investigated and calculated results of the energy characteristics of models of the heterogeneous dissipation and accumulating devices of mechanical energy developed on the basis of abovementioned effects.

The aim of this work is to simulate operating process in the aircraft fuel systems, with consideration of external influencing factors. The authors propose a new technique of simulating fuel consumption from fuel tanks during the flight along the trajectory and maneuvering; this technique is based on application of CAD systems and a specially developed finite element FuelTanks solver. The efficiency of this method was demonstrated on a specific example; calculation results were confirmed experimentally. Application domain for the developed method and mathematical software is a wide class of aircraft pneumatic-hydraulic systems along with ground systems which use pressure feed systems. Further development of the work presupposes software product development that follows the whole cycle of creating pneumatic-hydraulic systems from front-end engineering to diagnostic engineering during the operation.

The authors consider problems of modeling processes in new types of damping devices, in which the working fluid is a two-phase system: a porous body -  a fluid which does  not wet it. On the basis of the theory of heterogeneous porous systems with phase changes they propose a mathematical model of non-stationary processes in a heterogeneous working fluid damper. Specific tasks for calculating micro-and macro parameters of the damping system are formulated. Numerical methods for solving these problems are developed.