scholarly journals Transition regime analytical solution to gas mass flow rate in a rectangular micro channel

2012 ◽  
Author(s):  
S. Kokou Dadzie ◽  
Nishanth Dongari
Keyword(s):  
Analytical Solution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Transition Regime ◽  
Micro Channel

scholarly journals Method of characteristics for the problems of stages of the serviceability check of elementary section of a gas pipeline for operation

2021 ◽  
Vol 2131 (3) ◽  
pp. 032117
Author(s):  
I K Khujaev ◽  
Kh Aminov ◽  
S Akhmadjonov ◽  
A Ismailov
Keyword(s):  
Analytical Solution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Method Of Characteristics ◽  
Gas Injection ◽  
Gas Pipeline ◽  
Dynamic State ◽  
Gas Dynamic ◽  
Elementary Section

Abstract The article is devoted to modeling the gas-dynamic state of an elementary section of a gas pipeline during gas injection and its outflow through the choke in the final section of the pipe and to solving these problems using the method of characteristics. The subject of the study is the gas-dynamic state of an elementary horizontal section of a gas pipeline in the process of checking its serviceability for operation. The processes of gas injection into the section and gas outflow from it, considered in the article, were modeled using the N.E. Zhukovsky formula on gas outflow into unbounded space in a framework of the short pipeline approach. The original equations are linearized by introducing the mass flow rate of gas and waves traveling in two directions. When solving the problem, the method of characteristics was applied; numerical results were obtained and analyzed using an analytical solution to the problem. The research methods are based on the laws of conservation of momentum and gas mass, the d’Alembert method for solving a system of hyperbolic equations and the methods of conducting a computational experiment. An analytical solution to the problem with a rupture caused by an instantaneous change in the gas pressure at the end of the section is obtained. It is shown that the process proceeds with the formation of compression and rarefaction waves, and their multiple reflections at the ends of the section. The gas in the section tends to a state of rest with time, and the changes in the mass flow rate and gas pressure are of exponential nature.

J0540106 Mass Flow Rate Measurement of Water Molecules through a Micro-channel

2015 ◽  
Vol 2015 (0) ◽  
pp. _J0540106--_J0540106-
Author(s):  
Kensuke TAKAMORI ◽  
Hiroki YAMAGUCHI ◽  
Osamu MABUCHI ◽  
Yu MATSUDA ◽  
Tomohide NIIMI
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Water Molecules ◽  
Micro Channel ◽  
Rate Measurement ◽  
Flow Rate Measurement

A CFD technique to investigate the chocked flow and heat transfer characteristic in a micro-channel heat sink

2015 ◽  
Vol 04 (02) ◽  
pp. 1550007 ◽  
Author(s):  
Ahmad Azari ◽  
Abdorrasoul Bahraini ◽  
Saeideh Marhamati
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Relative Error ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Sink ◽  
Stanton Number ◽  
Micro Channel ◽  
Flow And Heat Transfer ◽  
Channel Exit

In this research, a Computational Fluid Dynamics (CFD) technique was used to investigate the effect of choking on the flow and heat transfer characteristics of a typical micro-channel heat sink. Numerical simulations have been carried out using Spalart–Allmaras model. Comparison of the numerical results for the heat transfer rate, mass flow rate and Stanton number with the experimental data were conducted. Relatively good agreement was achieved with maximum relative error 16%, and 8% for heat transfer and mass flow rate, respectively. Also, average relative error 9.2% was obtained for the Stanton number in comparison with the experimental values. Although, the results show that the majority of heat was transferred in the entrance region of the channel, but the heat transfer in micro-channels can also be affected by choking at channel exit. Moreover, the results clearly show that, the location where the flow is choked (at the vicinity of the channel exit) is especially important in determining the heat transfer phenomena. It was found that Spalart–Allmaras model is capable to capture the main features of the choked flow. Also, the effects of choking on the main characteristics of the flow was presented and discussed.

On the thermally-driven gas flow through divergent micro/nanochannels

2017 ◽  
Vol 28 (12) ◽  
pp. 1750143 ◽  
Author(s):  
Mohammad Sajjad Mozaffari ◽  
Ehsan Roohi
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Constitutive Law ◽  
Thermal Mass ◽  
Transition Regime ◽  
Aspect Ratios ◽  
Wide Range ◽  
Thermally Driven

A detailed study on thermally driven flows through divergent micro/nanochannels is presented. Rarefied gas flow behavior and thermal mass flow rate were investigated with different divergence angles ranging between 0[Formula: see text] and 7[Formula: see text] at two aspect ratios ([Formula: see text]) using particle-based direct simulation Monte-Carlo (DSMC) method. We compare our DSMC solutions for normalized thermal mass flow rate with the numerical solution of the Boltzmann–Krook–Walender (BKW) model and Bhatnagar–Gross–Krook (BGK) model and asymptotic theory over a wide range of Knudsen number in the transition regime. The flow field properties including Mach number, pressure, overall temperature and magnitude of shear stress are examined in detail. Based on our analysis, we observed an approximately constant velocity and pressure distribution at a microchannel with a small opening angle. Our results also demonstrate that the heat lines from weakly nonlinear form of Sone constitutive law and DSMC show good agreement at low Knudsen numbers. Moreover, we show that the effect of divergence angle is influential in increasing normalized thermal mass flow rate at early transition regime.

scholarly journals Effect of Hydrogen Refueling Parameters on Final State of Charge

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 645 ◽  
Author(s):  
Jinsheng Xiao ◽  
Shuo Ma ◽  
Xu Wang ◽  
Shanshan Deng ◽  
Tianqi Yang ◽  
...  
Keyword(s):  
Differential Equation ◽  
Analytical Solution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Balance Equation ◽  
State Of Charge ◽  
Hydrogen Density ◽  
Hydrogen Mass ◽  
Metallic Liner

The state of charge (SOC) is a key indicator to show whether a compressed hydrogen tank meets refueling requirements, so it is worth to study effects of the refueling parameters on it. A new SOC analytical solution is obtained based on a simple thermodynamic model. By applying a mass balance equation and an energy balance equation for a hydrogen storage system, a differential equation was obtained. An analytical solution of hydrogen temperature was deduced from the solution of the differential equation, then an analytical solution of hydrogen mass was further deduced based on the analytical solution of hydrogen temperature with some mathematical modifications. By assuming the hydrogen density inside the tank is uniform, the SOC, which defined as a ratio of hydrogen density to the full-fill density, can be transformed to be the ratio of hydrogen mass to the full-fill mass. The hydrogen mass can be calculated from analytical solution of hydrogen mass, while the full-fill mass is supposed to be a constant value. The full-fill density of 35 MPa and 70 MPa tanks at 15 °C are respectively 24.0 g/L and 40.2 g/L, and if the volume of the tank is known, the full-fill mass can also be calculated. The analytical solution of SOC can be unitized to express the reference data, the contributions of inflow temperature and mass flow rate on SOC are presented for a Dynetek type III tank (40 L, metallic liner) and a Hexagon type IV tank (29 L, plastic liner). In addition, the two-parameter effect of inflow temperature and mass flow rate on SOC are presented. The Nusselt number and Reynolds number are utilized to modify the analytical model, the relationship between SOC and refueling parameters can be obtained through the method of fitting. The fittings show a good agreement. The SOC can be determined from the refueling parameters based on the model with more physical meaning. The method developed in this research can be applied to the control algorithm of refueling stations to ensure safety and efficiency.

The standard unit mass flow rate of gas-liquid mixtures

2020 ◽  
pp. 13-16
Author(s):  
V.N. Petrov ◽  
◽  
V.F. Sopin ◽  
L.A. Akhmetzyanova ◽  
Ya.S. Petrova ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Liquid Mixtures ◽  
Unit Mass ◽  
Standard Unit

Prediction of Leakage Mass Flow Rate Through Gas Springs

1987 ◽  
Author(s):  
Roberto Bruno Bossio ◽  
Vincenzo Naso ◽  
Marian Cichy ◽  
Boleslaw Pleszewski
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate
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