RESEARCH OF THE POSSIBILITY OF TRANSMISSION OF LIQUEFIED NATURAL GAS THROUGH A PIPELINE BY A NON-PRESSURE METHOD

This article discusses the problems of transmission of liquefied natural gas through a non-pressure pipeline from a stationary storage facility to a transport cryogenic tank and ways to solve them. Theoretical studies have been carried out, including mathematical modeling of thermal and hydrodynamic processes during the transmission of liquefied natural gas through a pipeline by a non-pressure method.

Heat and mass transfer of multicomponent gas mixtures in cryogenic tank of automotive equipment

The use of liquefied gas as a motor fuel for automotive equipment has both certain advantages and significant problems. The paper deals with the solution of one of the main problems, reducing the speed of the phase transition of liquefied methane in a cryogenic tank in the mode of drainage-free storage. In solving the above problem, the process of convective heat and mass transfer caused by the chemical and physical state of natural gas and the external heat flow was investigated. The two-phase state of the gas is unstable in the event of an increase in heat input from the environment, which causes an imbalance of pressure and temperature in the volumes of the liquid and gaseous parts of the gas and creates the risk of an emergency. To prevent the formation of critical gas pressure in a cryogenic tank, a method is proposed for calculating the phase transition of liquefied methane to determine the volume fraction of vaporized gas using equilibrium constants, which will allow developing an algorithm for the technological process of gas recirculation in a specially designed tank design. This will also allow you to choose the best option for a thermal insulation layer that can reduce the rate of penetration of heat from the environment and increase the period of drainage-free storage of liquefied natural gas by 1.5-2 times.

Thermodynamic model of cryogenic fuel tank processes

A new procedure is created for the calculation of heat and mass transfer processes in a cryogenic rocket tank. This simplified method is based on the assumption about homogeneity of temperature in liquid and vapor phase of a fuel component. This assumption made this model useful for such regime as refueling, self-pressurization, pressurization during engine working and other. As the example of method applicability, some calculation is made for refueling of KVTK upper stage to estimate component losses. For the self-pressurization regime, the results of the calculation is compared with experimental data for one cylindrical and one spherical hydrogen tanks. This comparison is shown that pressure rise rate in a full tank several times upper than in the calculations. But for the low level of liquid hydrogen the accuracy of this method is significantly increased. As the result, this procedure is recommended as a lover score of pressure rise during self-pressurization. Key words: cryogenic propellant tank, cryogenic fuel storage, cryogenic tank processes, mathematical modelling, calculation method, refueling, mass-average temperature.

Mathematical model of the liquefied methane phase transition in the cryogenic tank of a vehicle

In order to increase the efficiency of using vehicles (VEH) in mining and quarrying conditions, it is necessary to improve the components of gas equipment (cryogenic tank, gas nozzles, fuel supply cryogenic tubes, etc.) for supplying liquefied natural gas to the engine, as well as storage of liquid methane in a cryogenic tank with a long service life. For this, it is necessary to consider the process of heat and mass transfer of liquefied natural gas in a two-phase liquid-gas medium, taking into account the phase transition in the closed volume of the cryogenic tank under consideration. The article presents a model of unsteady heat and mass transfer of a two-phase liquefied methane medium in a developed two-tank cryogenic tank using a Cartesian coordinate system with fractional control volumes in space. The experimental data confirm the efficiency of using a cryogenic tank on the VEH platform, in which the run on liquefied methane compared to standard fuels is tripled, the shelf life of liquefied gas in the proposed cryogenic tank is 2-2.5 times longer than in the standard one.