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

Abstract 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.

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

Записки Горного института ◽

10.31897/pmi.2020.3.337 ◽

2020 ◽

Vol 243 ◽

pp. 337

Author(s):

Otari Didmanidze ◽

Alexander Afanasev ◽

Ramil Khakimov

Keyword(s):

Phase Transition ◽

Mass Transfer ◽

Natural Gas ◽

Heat And Mass Transfer ◽

Liquefied Natural Gas ◽

Closed Volume ◽

Two Phase ◽

Cryogenic Tank ◽

Cartesian Coordinate ◽

Control Volumes

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.

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Numerical Study on Flow and Heat and Mass Transfer in Pulsating Heat Pipe

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2019-4012 ◽

2019 ◽

Author(s):

Jian-Hong Liu ◽

Fu-Min Shang ◽

Nikolay Efimov

Keyword(s):

Numerical Simulation ◽

Mass Transfer ◽

Heat Pipe ◽

Gas Phase ◽

Heat And Mass Transfer ◽

Mixture Model ◽

Volume Fraction ◽

Pulsating Heat Pipe ◽

Two Phase ◽

Pipe Model

Abstract Numerical simulation was performed to establishing a two-dimensional pulsating heat pipe model, to investigate the flow and heat transfer characteristics in the pulsating heat pipe by using the Mixture and Euler models, which were unsteady models of vapor-liquid two-phase, based on the control-volume numerical procedure utilizing the semi-implicit method. Through comparing and analyzing the volume fraction and velocity magnitude of gas phase to decide which model was more suitable for numerical simulation of the pulsating heat pipe in heat and mass transfer research. It was showed there had gas phase forming in stable circulation flow in the heating section, the adiabatic section using the Mixture and Euler models respectively, and they were all in a fluctuating state at 10s, besides, the pulsating heat pipe had been starting up at 1s and stabilizing at 5s, it was all found that small bubbles in the heat pipe coalescing into large bubbles and gradually forming into liquid plugs and gas columns from the contours of volume fraction of the gas phase; through comparing the contours of gas phase velocity, it could be seen that there had further stably oscillating flow and relatively stabler gas-liquid two-phase running speed in the pulsating heat pipe used the Mixture model, the result was consistent with the conclusion of the paper[11] extremely, from this it could conclude that the Mixture model could be better simulate the vaporization-condensation process in the pulsating heat pipe, which could provide an effective theoretical support for further understanding and studying the phase change heat and mass transfer mechanism of the pulsating heat pipe.

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