The effect of turbulent mixing on the moving liquid layer energy conversion into the internal energy of a compressed gas and the character of the gas compression

2002 ◽  
Vol 28 (2) ◽  
pp. 108-109 ◽  
Author(s):  
M. V. Bliznetsov ◽  
I. G. Zhidov ◽  
E. E. Meshkov ◽  
N. V. Nevmerzhitskii ◽  
E. D. Sen’kovskii ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Internal Energy ◽  
Liquid Layer ◽  
Turbulent Mixing ◽  
Gas Compression ◽  
Compressed Gas ◽  
Moving Liquid

scholarly journals Long-Term Analysis of Atmospheric Energetics Components over the Mediterranean, Middle East and North Africa

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 976
Author(s):  
Silas Michaelides
Keyword(s):  
Middle East ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Internal Energy ◽  
North Africa ◽  
Climatic Data ◽  
Monthly Means ◽  
Seasonal Behavior ◽  
Long Term Changes

In this research, one aspect of the climate that is not commonly referred to, namely, the long-term changes in the components of the atmospheric energy, is investigated. In this respect, the changes in four energy forms are considered, namely, Kinetic Energy (KE), Thermal Energy (TE), Internal Energy (IE), Potential Energy (PE) and Latent Energy (LE); the Energy Conversion (EC) between Kinetic Energy and Potential plus Internal Energy (PIE) is also considered. The area considered in this long-term energetics analysis covers the entire Mediterranean basin, the Middle East and a large part of North Africa. This broad geographical area has been identified by many researchers as a hot spot of climate change. Analyses of climatic data have indeed shown that this region has been experiencing marked changes regarding several climatic variables. The present energetics analysis makes use of the ERA-Interim database for the period from 1979 to 2018. In this 40-year period, the long-term changes in the above energetics components are studied. The monthly means of daily means for all the above energy forms and Energy Conversion comprise the basis for the present research. The results are presented in the form of monthly means, annual means and spatial distributions of the energetics components. They show the dominant role of the subtropical jet-stream in the KE regime. During the study period, the tendency is for KE to decrease with time, with this decrease found to be more coherent in the last decade. The tendency for TE is to increase with time, with this increase being more pronounced in the most recent years, with the maximum in the annual mean in KE noted in 2015. The sum of Potential and Internal energies (PIE) and the sum of Potential, Internal and Latent energies (PILE) follow closely the patterns established for TE. In particular, the strong seasonal influence on the monthly means is evident with minima of PIE and PILE noted in winters, whereas, maxima are registered during summers. In addition, both PIE and PILE exhibit a tendency to increase with time in the 40-year period, with this increase being more firmly noted in the more recent years. Although local conversion from KE into PIE is notable, the area averaging of EC shows that the overall conversion is in the direction of increasing the PIE content of the area at the expense of the KE content. EC behaves rather erratically during the study period, with values ranging from 0.5 to 3.7 × 102 W m−2. Averaged over the study area, the Energy Conversion term operates in the direction of converting KE into PIE; it also lacks a seasonal behavior.

Solute collection after off-line supercritical fluid extraction into a moving liquid layer

1994 ◽  
Vol 685 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Jin Veji-osta ◽  
Josef Planeta ◽  
Milena Mikešová ◽  
Alena Ansorgová ◽  
Pavel Karásek ◽  
...  
Keyword(s):  
Supercritical Fluid Extraction ◽  
Supercritical Fluid ◽  
Liquid Layer ◽  
Fluid Extraction ◽  
Moving Liquid

A simple ventilator suitable for respiratory gas studies

1978 ◽  
Vol 44 (4) ◽  
pp. 640-641
Author(s):  
C. P. Heneghan ◽  
D. D. Martindale ◽  
J. P. Blackburn
Keyword(s):  
Dead Space ◽  
Minute Volume ◽  
Valve Timing ◽  
Gas Compression ◽  
Compressed Gas ◽  
The Subject ◽  
Human Use ◽  
Compression Effects ◽  
Gas Supply

A simple ventilator is described where a spring-loaded bellows is filled from a compressed gas supply. The outflow from the bellows to the subjects is controlled by solenoid valves. The device is a minute volume divider and the durations of inspiration and expiration are set by timers that operate the solenoid valves. The valves are positioned near the subject to minimize dead space and gas compression effects. Precise valve timing ensures separation of inspirate and expirate. The ventilator is suitable for respiratory gas studies on animals and may be modified for human use if required.

The effect of turbulent mixing on the dynamics of a liquid layer accelerated by a compressed air flow

2002 ◽  
Vol 28 (2) ◽  
pp. 87-89 ◽  
Author(s):  
I. G. Zhidov ◽  
E. E. Meshkov ◽  
N. V. Nevmerzhitskii ◽  
I. G. Pylev ◽  
E. A. Sotskov
Keyword(s):  
Liquid Layer ◽  
Turbulent Mixing ◽  
Air Flow ◽  
Compressed Air

Numerical Modeling of Liquid Piston Gas Compression

2009 ◽  
Author(s):  
Cecil Piya ◽  
Indraneel Sircar ◽  
James D. Van de Ven ◽  
David J. Olinger
Keyword(s):  
Input Power ◽  
High Rate ◽  
Heat Extraction ◽  
Thermal Fluids ◽  
Gas Compression ◽  
Compressed Gas ◽  
Liquid Piston ◽  
Transfer Mechanisms ◽  
System Characteristics ◽  
Double Digit

Prior research has shown that the use of liquid-pistons in place of conventional solid pistons within gas compression technologies can significantly improve the efficiency of gas compression. The liquid-piston provides the prospect for a consistent and high rate of heat extraction from the compressed gas during system operation. Consequently, the input power requirements during each individual compression are lowered. To validate this concept, analytical studies of the thermal-fluids and heat transfer mechanisms during gas compression were performed. The analysis involved the development of a numerical model, using the finite-difference method, which simulated a single compression stroke and quantified the crucial parameters during compression. This model was utilized to obtain theoretical efficiency values and to recognize optimal system characteristics. The results obtained from the simulation indicated double-digit increase in efficiency with the introduction of the liquid-piston.

scholarly journals Understanding mixing efficiency in the oceans: do the nonlinearities of the equation of state for seawater matter?

Ocean Science ◽  
2009 ◽  
Vol 5 (3) ◽  
pp. 271-283 ◽  
Author(s):  
R. Tailleux
Keyword(s):  
Equation Of State ◽  
Potential Energy ◽  
Energy Conversion ◽  
Internal Energy ◽  
Molecular Diffusion ◽  
Rate Of Change ◽  
Gravitational Potential Energy ◽  
Mixing Efficiency ◽  
Buoyancy Frequency ◽  
Boussinesq Fluid

Abstract. There exist two central measures of turbulent mixing in turbulent stratified fluids that are both caused by molecular diffusion: 1) the dissipation rate D(APE) of available potential energy APE; 2) the turbulent rate of change Wr, turbulent of background gravitational potential energy GPEr. So far, these two quantities have often been regarded as the same energy conversion, namely the irreversible conversion of APE into GPEr, owing to the well known exact equality D(APE)=Wr, turbulent for a Boussinesq fluid with a linear equation of state. Recently, however, Tailleux (2009) pointed out that the above equality no longer holds for a thermally-stratified compressible, with the ratio ξ=Wr, turbulent/D(APE) being generally lower than unity and sometimes even negative for water or seawater, and argued that D(APE) and Wr, turbulent actually represent two distinct types of energy conversion, respectively the dissipation of APE into one particular subcomponent of internal energy called the "dead" internal energy IE0, and the conversion between GPEr and a different subcomponent of internal energy called "exergy" IEexergy. In this paper, the behaviour of the ratio ξ is examined for different stratifications having all the same buoyancy frequency N vertical profile, but different vertical profiles of the parameter Υ=α P/(ρCp), where α is the thermal expansion coefficient, P the hydrostatic pressure, ρ the density, and Cp the specific heat capacity at constant pressure, the equation of state being that for seawater for different particular constant values of salinity. It is found that ξ and Wr, turbulent depend critically on the sign and magnitude of dΥ/dz, in contrast with D(APE), which appears largely unaffected by the latter. These results have important consequences for how the mixing efficiency should be defined and measured in practice, which are discussed.

In‐Depth Analysis of the Internal Energy Conversion of Nuclear Batteries and Radiation Degradation of Key Materials

2020 ◽  
Vol 8 (12) ◽  
pp. 2000667
Author(s):  
Tongxin Jiang ◽  
Zhiheng Xu ◽  
Caifeng Meng ◽  
Yunpeng Liu ◽  
Xiaobin Tang
Keyword(s):  
Energy Conversion ◽  
Internal Energy ◽  
Depth Analysis ◽  
Radiation Degradation ◽  
Nuclear Batteries

scholarly journals Study of the Reynolds Number Effect on the Process of Instability Transition Into the Turbulent Stage

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
N. V. Nevmerzhitskiy ◽  
E. A. Sotskov ◽  
E. D. Sen'kovskiy ◽  
O. L. Krivonos ◽  
A. A. Polovnikov ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Turbulent Mixing ◽  
High Speed ◽  
Reynolds Numbers ◽  
Short Wave ◽  
Solid Particles ◽  
Reynolds Number Effect ◽  
Long Wave ◽  
Compressed Gas ◽  
Perturbation Growth

The results of the experimental study of the Reynolds number effect on the process of the Rayleigh–Taylor (R-T) instability transition into the turbulent stage are presented. The experimental liquid layer was accelerated by compressed gas. Solid particles were scattered on the layer free surface to specify the initial perturbations in some experiments. The process was recorded with the use of a high-speed motion picture camera. The following results were obtained in experiments: (1) Long-wave perturbation is developed at the interface at the Reynolds numbers Re < 104. If such perturbation growth is limited by a hard wall, the jet directed in gas is developed. If there is no such limitation, this perturbation is resolved into the short-wave ones with time, and their growth results in gas-liquid mixing. (2) Short-wave perturbations specified at the interface significantly reduce the Reynolds number Re for instability to pass into the turbulent mixing stage.

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