Implementation of Knudsen Layer Phenomena in Rarefied High-Speed Gas Flows

In this study we will investigate an interesting collective behavior of candles. It has been observed that when several candles burn close to each other they form a common flame that exhibits oscillations in size and brightness. If two such oscillators burn together, they interact and the oscillations of the resultant system depend on the distance between them. The aim of this investigation, inspired by Problem 5 of the International Young Physicists Tournament in 2021, is to theoretically explain the phenomenon through overlapping of hot gas flows and radiation, as well as to check our understanding and measure additional parameters experimentally using advanced techniques, such as high speed schlieren photography.

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Parameters of Pulsed Discharge Plasma in High-Speed Gas Flows

High Temperature ◽

10.1134/s0018151x2006019x ◽

2020 ◽

Vol 58 (6) ◽

pp. 754-760

Author(s):

L. V. Shibkova ◽

V. M. Shibkov ◽

A. A. Logunov ◽

D. S. Dolbnya ◽

K. N. Kornev

Keyword(s):

High Speed ◽

Discharge Plasma ◽

Gas Flows ◽

Pulsed Discharge ◽

Pulsed Discharge Plasma

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An extended Navier-Stokes formulation for gas flows in the Knudsen layer near a wall

EPL (Europhysics Letters) ◽

10.1209/0295-5075/80/24001 ◽

2007 ◽

Vol 80 (2) ◽

pp. 24001 ◽

Cited By ~ 61

Author(s):

Z. L. Guo ◽

B. C. Shi ◽

C. G. Zheng

Keyword(s):

Knudsen Layer ◽

Navier Stokes ◽

Gas Flows

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Macroscopic Equations for High-Speed Rarefied Monatomic Gas Flows past Cold Bodies

10.1063/1.1941521 ◽

2005 ◽

Author(s):

Alexander I. Erofeev

Keyword(s):

High Speed ◽

Gas Flows ◽

Monatomic Gas ◽

Macroscopic Equations

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IMPROVING THE EFFICIENCY OF THE FUNCTIONING OF GAS PIPELINES, TAKING INTO ACCOUNT THE STRUCTURAL FEATURES OF GAS FLOWS

NEWS of National Academy of Sciences of the Republic of Kazakhstan ◽

10.32014/2021.2518-170x.59 ◽

2021 ◽

Vol 447 (3) ◽

pp. 34-39

Author(s):

Elman Kh. Iskandarov

Keyword(s):

High Speed ◽

Gas Flow ◽

Structural Changes ◽

Oil And Gas ◽

Structural Features ◽

Transportation Systems ◽

Gas Condensate ◽

Gas Flows ◽

Gas Pipelines ◽

Processing Depth

The multi-phase and different composition of gas flows during the development of offshore oil and gas-condensate fields leads to high costs of energy in the system of in-field storage and transportation of well products. The analysis of the existing storage and transportation systems of gas-condensate mixtures shows that the geophysical nature and complexity of the internal structure of the transported fluids must be taken into account when choosing the mode parameters and calculation schemes of the pipelines. High-speed gas lines can be operated in a so-called "dry" mode, in which the liquid is carried along with the gas, the pipeline profile is relatively straight, without ups and downs. In this case, the formation of so-called "stagnant zones" in the pipeline is excluded. However, if the processing depth of the gas does not allow it to be transported in a single-phase state, then the condensing gas factor manifests itself. The hydraulic characteristics of vertical ups and downs on offshore pipelines are complicated, and pipelines are often filled with water and condensate. As a result, the pressure in the pipeline increases and the location of the collection point for condensing gases away from the production site can cause major problems. If we characterize oil and gas-condensate flows as a dynamic system in which alternating structural changes take place, the question of whether these systems are fractal is of great scientific interest. Based on the change in the fractal value, it is possible to diagnose structural changes during the transportation of various systems, including condensing gases in the pipelines. In this article the modes of change of basic parameters of a gas flow (pressure, flow rate and temperature) on various lines of a gas pipeline for the purpose of the producing of diagnostic criterion for revealing of liquid inclusions as a part of transported gas are investigated in this article. It is established, that in the presence of liquid inclusions at movement of gas flows there are the structural changes peculiar to fluid systems, systems which can be identified by variations of fractal dimensions of flowcharacteristics. Studies have shown that the study of the dynamics of structural changes in gas flows can play a role in diagnosing the formation of liquid phase embryos in gas pipelines. For this purpose, diagnostics for the movement of gas streams accompanied by liquid deposits in the pipelines has been proposed.

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Design and Testing of a Prototype Atmospheric Gas Collection Apparatus for a Mission to Mars

Aerospace ◽

10.1115/imece2006-14499 ◽

2006 ◽

Author(s):

John D. Bernardin ◽

Snezana Konecni ◽

Roger Wiens

Keyword(s):

High Speed ◽

High Vacuum ◽

Martian Atmosphere ◽

Gas Flows ◽

Cfd Model ◽

Sample Collection ◽

Sorption System ◽

Return Journey ◽

Pass Through ◽

Design And Testing

A novel spacecraft, the Sample Collection for Investigation of Mars (SCIM), was proposed for the collection and return of atmospheric gas and dust samples from the martian atmosphere. The SCIM mission, part of NASA's Mars Exploration Strategy, would allow scientists to greatly enhance our understanding of Mars' water, climate, and geological evolution by studying the element and isotopic composition of the gas and dust. The SCIM spacecraft was proposed to collect its samples during a single high-speed pass through the martian atmosphere at an altitude of 37 km and return the samples back to earth. For the atmospheric gas sampling aspect the SCIM employs the Atmospheric Collection Experiment (ACE), a dual-component apparatus consisting of a passive and a cryogenic sorption gas collection system. Each of these systems possesses a collection vessel that is initially under high vacuum. At the time of entry into the martian atmosphere, valves on SCIM open and gas flows into the parallel-plumbed passive and cryogenic sorption gas collection systems. The passive system simply allows the incoming gas to fill an initially evacuated 1 Liter vessel. The cryogenic sorption system employs a Joule-Thompson cryocooler and sorption medium that initially condenses and captures the incoming gas. As the SCIM begins to exit the atmosphere isolation valves close and trap the gas samples in their collection systems for the return journey back to earth. The minimum SCIM mission goal was to collect 100 cm3 @STP(≈ 0.2 g) of martian atmospheric gas and the ACE was being designed to gather 1000 cm3 @STP (≈ 2.0 g) using both the passive and cryogenic systems. The volumes referred to above correspond to standard temperature and pressure on Earth (e.g., STP). The goals of this study were to prove the gas collection concepts mentioned above and develop the numerical and experimental tools to allow for the optimization of a flight worthy ACE. This paper discusses the design, analysis, and testing of a prototype ACE. First, more specific details on the design and testing methodology for the prototype are presented. Next, the development of a computational fluid dynamics (CFD) model is discussed. Finally, empirical pressure data from the prototype tests are used to assess the performances of the passive and cryogenic sorption gas collection systems and are compared to numerical pressure predictions to provide a benchmark for the CFD model. Results indicate that the prototype ACE is capable of meeting the design goal of 1000 cm3 @STP (2.0 g) of total gas collection.

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