Maria Koroleva
ul. T. Baramzinoi 34, Izhevsk, 426067 Russia
Udmurt Federal Research Center UB RAS
Publications:
Korepanov M. A., Koroleva M. R., Mitrukova E. A., Nechay A. N.
Nonlinear Effects of Krypton Flow in a Micronozzle with a Cylindrical Tube
2022, Vol. 18, no. 3, pp. 411-422
Abstract
This paper considers krypton flow in a micronozzle with a cylindrical tube. A standardized
conical nozzle elongated with cylindrical portion performs gas discharge into a vacuum chamber
at a pressure of $10^{−2}$ Pa. Under such conditions, a low temperature area is formed in the central
part of the jet with gas condensation. The particles are entrained by the gas flow. The portion
with a constant section behind the nozzle should focus the supersonic flow part and the condensed
particle flow and also decrease particle dispersion behind the nozzle throat.
The paper expresses a mathematical model of homogeneous gas motion with respect to
formation processes and the growth of condensation nuclei. Since the condensed particles are
small, the research is carried out with a single velocity motion model. The results obtained
have shown that the application of the cylindrical tube leads to nonlinear flow effects. The flow
responds to: the geometrical exposure related to flow transition from the conical diverging nozzle
into the cylindrical tube, heat exposure and mass outflow due to particle formation and growth,
and considerable friction force exposure due to the small sizes of the channel. The sum total
ofthese factors leads to an insignificant deceleration of the supersonic flow part and highly impacts
condensation.
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Raeder T., Tenenev V. A., Koroleva M. R., Mishchenkova O. V.
Nonlinear Processes in Safety Systems for Substances with Parameters Close to a Critical State
2021, Vol. 17, no. 1, pp. 119-138
Abstract
The paper presents a modification of the digital method by S. K. Godunov for calculating
real gas flows under conditions close to a critical state. The method is generalized to the case of
the Van der Waals equation of state using the local approximation algorithm. Test calculations
of flows in a shock tube have shown the validity of this approach for the mathematical description
of gas-dynamic processes in real gases with shock waves and contact discontinuity both in areas
with classical and nonclassical behavior patterns. The modified digital scheme by Godunov with
local approximation of the Van der Waals equation by a two-term equation of state was used for
simulating a spatial flow of real gas based on Navier – Stokes equations in the area of a complex
shape, which is characteristic of the internal space of a safety valve. We have demonstrated that,
under near-critical conditions, areas of nonclassical gas behavior may appear, which affects the
nature of flows. We have studied nonlinear processes in a safety valve arising from the movement
of the shut-off element, which are also determined by the device design features and the gas
flow conditions.
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