Heat exchange near the critical point of a body within a supersonic two-phase jet

1994 ◽  
Vol 34 (5) ◽  
pp. 694-700
Author(s):  
A. L. Levin
Keyword(s):  
Heat Exchange ◽  
Critical Point ◽  
Two Phase

scholarly journals Effects of Polydispersity on the Phase Behavior of Additive Hard Spheres in Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1543
Author(s):  
Luka Sturtewagen ◽  
Erik van der Linden
Keyword(s):  
Phase Behavior ◽  
Critical Point ◽  
Volume Fraction ◽  
Hard Spheres ◽  
Second Virial Coefficient ◽  
Two Phase ◽  
Different Types ◽  
Asymmetric Partitioning ◽  
Average Size ◽  
Liquid Liquid Phase Separation

The ability to separate enzymes, nucleic acids, cells, and viruses is an important asset in life sciences. This can be realised by using their spontaneous asymmetric partitioning over two macromolecular aqueous phases in equilibrium with one another. Such phases can already form while mixing two different types of macromolecules in water. We investigate the effect of polydispersity of the macromolecules on the two-phase formation. We study theoretically the phase behavior of a model polydisperse system: an asymmetric binary mixture of hard spheres, of which the smaller component is monodisperse and the larger component is polydisperse. The interactions are modelled in terms of the second virial coefficient and are assumed to be additive hard sphere interactions. The polydisperse component is subdivided into sub-components and has an average size ten times the size of the monodisperse component. We calculate the theoretical liquid–liquid phase separation boundary (the binodal), the critical point, and the spinodal. We vary the distribution of the polydisperse component in terms of skewness, modality, polydispersity, and number of sub-components. We compare the phase behavior of the polydisperse mixtures with their concomittant monodisperse mixtures. We find that the largest species in the larger (polydisperse) component causes the largest shift in the position of the phase boundary, critical point, and spinodal compared to the binary monodisperse binary mixtures. The polydisperse component also shows fractionation. The smaller species of the polydisperse component favor the phase enriched in the smaller component. This phase also has a higher-volume fraction compared to the monodisperse mixture.

Visualization of Supercritical Carbon Dioxide Flow Through a Converging-Diverging Nozzle

2019 ◽  
Author(s):  
Chang Hyeon Lim ◽  
Gokul Pathikonda ◽  
Sandeep Pidaparti ◽  
Devesh Ranjan
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Critical Point ◽  
High Speed ◽  
Operating Conditions ◽  
Higher Plant ◽  
Two Phase ◽  
Pressure Profiles ◽  
Flow Through ◽  
Supercritical Carbon

Abstract Supercritical carbon dioxide (sCO2) power cycles have the potential to offer a higher plant efficiency than the traditional Rankine superheated/supercritical steam cycle or Helium Brayton cycles. The most attractive characteristic of sCO2 is that the fluid density is high near the critical point, allowing compressors to consume less power than conventional gas Brayton cycles and maintain a smaller turbomachinery size. Despite these advantages, there still exist unsolved challenges in design and operation of sCO2 compressors near the critical point. Drastic changes in fluid properties near the critical point and the high compressibility of the fluid pose several challenges. Operating a sCO2 compressor near the critical point has potential to produce two phase flow, which can be detrimental to turbomachinery performance. To mimic the expanding regions of compressor blades, flow through a converging-diverging nozzle is investigated. Pressure profiles along the nozzle are recorded and presented for operating conditions near the critical point. Using high speed shadowgraph images, onset and growth of condensation is captured along the nozzle. Pressure profiles were calculated using a one-dimensional homogeneous equilibrium model and compared with experimental data.

The effect of vapor content on the heat-exchange crisis in nonequilibrium two-phase fluxes

1972 ◽  
Vol 32 (5) ◽  
pp. 465-466
Author(s):  
L. A. Adamovich ◽  
G. M. Dvorina ◽  
V. G. Sytin
Keyword(s):  
Heat Exchange ◽  
Two Phase

HEAT EXCHANGE PROCESSES IN POWER SEMICONDUCTOR CONVERTER INSTALLATIONS WITH EVAPORATIVE AIR COOLING

2017 ◽  
pp. 140-147
Author(s):  
Igor Kiselev ◽  
Sergey Urushev ◽  
Igor Ivanov ◽  
Yulia Vodopyanova
Keyword(s):  
Heat Exchange ◽  
Semiconductor Devices ◽  
Practical Importance ◽  
Structural Features ◽  
Air Cooling ◽  
Two Phase ◽  
Power Semiconductor ◽  
Semiconductor Converter ◽  
Exchange Processes ◽  
Improve Reliability

Objective: To improve reliability and endurance of semiconductor devices by means of heat exchange processes optimization of installations with evaporative air cooling. Methods: Design features analysis of cooling installations was applied. Results: The structural features of “a twophase thermal siphon” for power semiconductor devices were described. Experimental research of power blocks of semiconductor converter installations with “two-phase thermal siphon” coolers was conducted. The values of maximum permissible currents upon the application of possible button-type instrument configurations with such coolers were obtained. Practical importance: Application of “two-phase thermal siphon” evaporative air coolers will make it possible to improve weight-size parameters of converter installations.

Influence of selected parameters on phenomena of two-phase flow and heat exchange in TSL furnace – numerical investigation

2017 ◽  
Vol 27 (12) ◽  
pp. 2799-2815
Author(s):  
Ewa Kolczyk ◽  
Zdzisław Miczkowski ◽  
Józef Czernecki
Keyword(s):  
Numerical Simulation ◽  
Heat Exchange ◽  
Liquid Slag ◽  
Gas Flow ◽  
Two Phase Flow ◽  
New Technology ◽  
Phase Flow ◽  
Two Phase ◽  
Content Type ◽  
Submerged Lance

Purpose The purpose of this study is application of a numerical simulation for determination of the influence of geometric parameters of a furnace and hydrodynamics of the gas introduced by a vertical submerged lance on the process of feed mixing and temperature distribution. Design/methodology/approach A numerical simulation with Phoenics software was applied for modeling of liquid phase movement and heat exchange between the gas supplied through a lance and the slag feed in a top submerged lance (TSL) furnace. The simulation of a two-phase flow of a slag–gas mixture based on the inter phase slip algorithm module was conducted. The influence of selected parameters, such as depth of lance submergence, gas flow rate and change of furnace geometry, on the phenomena of movement was studied. Findings Growth of dynamics of mixing with the depth of lance submergence and with increase of gas velocity in the lance was observed. Formation of a recirculation zone in the liquid slag was registered. Movement of the slag caused by the gas flow brought homogenization of the temperature field. Originality/value The study applied the simulation of a two-phase flow in the liquid slag–gas system in steady state, taking into account heat transfer between phases. It provides possibilities for optimization and selection of process parameters within the scope of the developed new technology using a TSL furnace.

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