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The paper is devoted to further development of numerical methods for simulation of riveting process during aircraft assembly (see [3, 4]). Algorithm modifications that increase computation accuracy, speed and complexity are given. These modifications involve the dual problem solving, incorporation of multiple calculation nets and special two stage procedure for calculation of deformations and stresses arising during assembly.

The experimental results of air evolution research by gravity fuel flow in a pipeline are presented. The pipe-line included an inclined section and a horizontal section connected by a bend. An orifice was installed at the entrance of the inclined pipeline section. The experimental investigations were carried out at pressures ranging from 20 to 80 kPa and temperatures varying between −20°C and +20°C. A significant fuel flow drop was observed by decreasing the pressure to a certain boundary value. This effect was caused by air evolution and the formation of two-phase air-fuel flow. It was shown that the boundary pressure value corresponding to the air evolution onset depended on temperature and fuel velocity values.