INVESTIGATION OF THE TEMPERATURE FACTOR INFLUENCE ON HEAT TRANSFER OF A BLUNT BODY MODEL IN THE HIGH-SPEED GAS FLOW

2010 ◽  
Vol 41 (6) ◽  
pp. 619-630
Author(s):  
Ivan V. Egorov ◽  
O. K. Kudin ◽  
Yu. N. Nesterov ◽  
B. V. Prusov
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Gas Flow ◽  
Blunt Body ◽  
Temperature Factor ◽  
Body Model

The Mechanics and Thermodynamics of Steady One-Dimensional Gas Flow

1947 ◽  
Vol 14 (4) ◽  
pp. A317-A336 ◽  
Author(s):  
Ascher H. Shapiro ◽  
W. R. Hawthorne
Keyword(s):  
Heat Transfer ◽  
Dimensional Analysis ◽  
High Speed ◽  
Gas Flow ◽  
Gas Injection ◽  
Wall Friction ◽  
Analytical Treatment ◽  
Area Change ◽  
One Dimensional ◽  
Recent Developments

Abstract Recent developments in the fields of propulsion, flow machinery, and high-speed flight have emphasized the need for an improved understanding of the characteristics of compressible flow. A one-dimensional analysis for flow without shocks is presented which takes into account the simultaneous effects of area change, wall friction, drag of internal bodies, external heat exchange, chemical reaction, change of phase, injection of gases, and changes in molecular weight and specific heat. The method of selecting independent and dependent variables, and the organization of the working equations, leads, it is believed, to a better understanding of the influence of the foregoing effects, and also simplifies greatly the analytical treatment of particular problems. Examples are given first of several simple types of flow, including (a) area change only; (b) heat transfer only; (c) wall friction only; and (d) gas injection only. In addition, examples of flow with combined effects are given, including (a) simultaneous friction and area change; (b) simultaneous friction and heat transfer; and (c) simultaneous liquid injection and evaporation. A one-dimensional analysis for flow through a discontinuity is presented, allowing for energy, shock, drag, and gas-injection effects, and for changes in gas properties. This analysis is applicable to such processes as: (a) the adiabatic normal shock; (b) combustion; (c) moisture condensation shocks; and (d) steady explosion waves.

Two-Phase Wakes in Adiabatic Liquid-Gas Flow Around a Cylinder

2020 ◽  
Author(s):  
Dohwan Kim ◽  
Matthew J. Rau
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
High Speed ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Water Channel ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Around A Cylinder ◽  
High Heat Transfer

Abstract Small tubes and fins have long been used as methods to increase surface area for convective heat transfer in single-phase flow applications. As demands for high heat transfer effectiveness has increased, implementing evaporative phase-change heat transfer in conjunction with small fins, tubes, and surface structures in advanced heat exchanger and heat sink designs has become increasingly attractive. The complex two-phase flow that results from these configurations is poorly understood, particularly in how the gas phase interacts with the flow structure of the wake created by these bluff bodies. An experimental study of liquid-gas bubbly flow around a cylinder was performed to understand these complex flow physics. A 9.5 mm diameter cylinder was installed horizontally within a vertical water channel facility. A high-speed camera captured the movement of the liquid-gas mixture around the cylinder for a range of bubble sizes. Liquid Reynolds number, calculated based on the cylinder diameter, was varied approximately from 100 to 3000. Time-averaged probability of bubble presence was calculated to characterize the cylinder wake and its effects on the bubble motion. The influence of the liquid Reynolds number, superficial air velocity, and bubble size is discussed in the context of the observed two-phase flow patterns.

scholarly journals Dynamics of dry spots in the liquid film moved by the gas flow in the mini-channel under intensive local heating

2018 ◽  
Vol 194 ◽  
pp. 01059
Author(s):  
Egor Tkachenko
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Gas Flow ◽  
Local Heating ◽  
Experimental Studies ◽  
Heater Surface ◽  
Two Phase ◽  
Heat Transfer Crisis ◽  
Typical Size ◽  
Dry Spot

Experimental studies of hydrodynamics and the heat transfer crisis were carried out for a two-phase stratified flow in a mini-channel with intensive heating from a heat source of 1x1 cm2. It has been established that as the heat flow increases, the total area of dry spots on the heater increases, but when a certain temperature of the heater surface reaches ≈100 °C, the area of dry spots begins to decrease. With the help of high-speed visualization (shooting speed 100000 frames per second), several stages of formation of a dry spot (a typical size of the order of 100 microns) were isolated. It was found that at a heat flux of 450 W/cm2 about 1 million dry spots per 1 second are formed and washed on the surface of the heater (1 cm2). The speed of the contact line when dry spot is forming reaches 10 m/s.

Flow and Heat-Transfer Simulation Based on CFD and Experimental Study during High-Pressure Gas Quenching

2010 ◽  
Vol 29-32 ◽  
pp. 1436-1440 ◽  
Author(s):  
Zhi Jian Wang ◽  
Xiao Feng Shang
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
High Pressure ◽  
Cooling Rate ◽  
High Speed ◽  
Gas Flow ◽  
Temperature Fields ◽  
Treatment Technology ◽  
Flow And Heat Transfer ◽  
Gas Quenching

High-pressure gas quenching is the heat treatment technology which quenches the works by use of high-pressure and high-speed flow gas. FLUENT software is used to simulate the process of gas-solid coupling flow and heat transfer in the nozzle-type vacuum high-pressure gas quenching furnace. The hot wire anemometer is used to measure the inlet velocities of nozzles, which provides the boundary conditions for computer simulation. By the computer simulation, the gas flow fields, work temperature fields and work cooling curves are attained. The results show that the big eddy current occurs at the corner of the furnace and the cooling rate of the work is slow there. Contrasting the simulating result of work cooling rate at the center of furnace with the actual measured one by the thermocouple, we find when work is cooled to the temperature of 430K, the simulating result is faster than the actual one about 50 seconds. The simulating results basically correspond with the actual trend of the gas quenching.

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