3 edition of Analysis of the transient compressible vapor flow in heat pipe found in the catalog.
Analysis of the transient compressible vapor flow in heat pipe
by National Aeronautics and Space Administration, For sale by the National Technical Information Service in [Washington, DC], [Springfield, Va
Written in English
|Statement||Jong Hoon Jang and Amir Faghri and Won Soon Chang.|
|Series||NASA contractor report -- 185119., NASA contractor report -- NASA CR-185119.|
|Contributions||Faghri, Amir., Chang, W. S., United States. National Aeronautics and Space Administration.|
|The Physical Object|
The dynamic behavior of the vapor flow in heat pipes is investigated at startup and during operational transients. The vapor is modeled as two-dimensional, compressible viscous flow in an enclosure with inflow and outflow boundary conditions. For steady-state and . 4. A pressure ratio of will cause sonic flow Applications 1. Nozzles and Diffusers and converging diverging nozzles 2. Turbines, fans & pumps 3. Throttles – flow regulators, an obstruction in a duct that controls pressure drop. 4. One Dimensional Isentropic Flow – compressible pipe flow.
UNM-HP accounts for both the inertia and friction forces in the vapor flow, and the vapor remains saturated. This heat pipe model has been verified successfully using experimental data of the vapor temperature along a short sodium heat pipe ( m) operated at different powers and Mach numbers up to (Ivanovskii et al., ; see Figures 31a. As the vapor flow in the pipe is a complicated problem, different approaches have been used to simply the problem. A detailed vapor flow analysis was performed by Busse, provided that the vapor flow is steady, laminar, and incompressible. HTPIPE was the first comprehensive heat pipe design and analysis code to be developed.
Bowman, W. J., and Hitchcock, J. E., , “Transient, Compressible Heat-Pipe Vapor Dynamics,” Proc. ASME National Heat Transfer Conf., Houston, TX, Vol. 1, pp. The transient behavior of vapor flow dunng the start-up phase of heat pipe operation has been analyzed in order to examine the flow patterns for high-input heat fluxes. Start-up is a transient process through which the heat pipe starts its operation from a staticcondition and arrives at steady-state operation. During a start-up transient. the working fluid of a heat pipe may initially be.
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The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual flow in cylindrical heat : Jong Hoon Jang, Amir Faghri, Won Soon Chang.
The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method.
The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat by: Abstract. The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method.
The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat by: Written by leading industry experts, Pressure Wave Analysis of Transient Flow in Pipe Distribution Systems is designed for use in advanced hydraulics and water resources engineering courses dealing with the design and analysis of municipal water supply and distribution : $ Abstract A complete mathematical model for transient two-dimensional heat pipes is presented.
The numerical results for both simulated compressible vapor flow with high Mach numbers and the vapor flow of a high-temperature heat pipe are compared with the experimental data in the literature. The transient responses of heat pipes to a pulsed heat input are also by: Analysis of the one-dimensional transient compressible vapor flow in heat pipes International Journal of Heat and Mass Transfer, Vol.
34, No. 8 An analysis of the vapor flow and the heat conduction through the liquid-wick and pipe wall in a heat pipe with single or multiple heat. Abstract: A computational model is developed for the analysis of the transient operation of a flat heat pipe. The analysis involves the solution of the two-dimensional continuity, momentum and energy equations coupled with the state equation in the vapor core, the transport equations for a porous medium in the wick, and the two-dimensional heat conduction equation in the heat pipe wall.
In the present paper, an analysis of the steady, compressible, one-dimensional, laminar flow of sodium vapor is presented for the case of a flat -type heat pipe with asymmetrical boundary condi'tions.
In addition, shear stress at the 1 iquid-vapor interface, variations of vapor. TRANSIENT ANALYSIS IN PIPE NETWORKS. Increase in void fraction due to latent heat flow is not considered. Wylie () investigated both gaseous and vapor cavitation using a discrete free gas model.
Free gas is lumped at discrete computing locations and pure liquid is assumed in between these locations. Small void fraction and isothermal. Compressible Fluid Flow Calculation Methods Article (PDF Available) in Chemical Engineering -New York- Mcgraw Hill Incorporated then Chemical Week Publishing Llc- (2) February Get this from a library.
Analysis of the transient compressible vapor flow in heat pipe. [Jong Hoon Jang; Amir Faghri; Won Soon Chang; United States. National Aeronautics and Space Administration.].
velocity distributions in transient and steady-state operation of heat pipes. Transient, compressible one-dimensional vapor flow in a cylindrical heat pipe was analyzed by Jang et al.
. Transient vapor flow dynamics were predicted at subsonic, sonic and supersonic speeds, and at high mass flow rates and high temperatures. Analysis of the one-dimensional transient compressible vapor flow in heat pipes.
International Journal of Heat and Mass Transfer, 34, – CrossRef Google Scholar. flow solutions, few investigations have examined the effect of a variable gLs compressibility factor on transient be he vi or.
The ~urpose. of this study is to. r~eveloiJ. and. ap~ly. the numerical equations of transient gas pipe flow based on 1) a constant ~as. compressibility factor ev81uated At the average of inlet and outlet. Adiabatic compressible flow is the flow where no heat is transferred to or from pipe like in short, perfectly insulated pipe.
The heat which is created due to flow friction is added to the flow and that amount of energy is actually acceptable. solutions of compressible flow, i.e. Fanno and Rayleigh flow. Fanno flow provides an analytical solution of compressible flow in a long slender pipe where incoming subsonic flow can be choked due to friction.
On the other hand, Raleigh flow provides analytical solution of frictionless compressible flow with heat transfer where incoming subsonic.
A first-order transient model of the vapor flow in a heat pipe was proposed by Jang et al. This model simulated heat pipe operation with one-dimensional compressible vapor flow in a porous pipe, accounting for laminar and turbulent skin friction.
The vapor flow patterns in heat pipes are examined during the start-up transient phase. The vapor core is modelled as a channel flow using a two dimensional compressible flow model. Kayode Coker, in Fortran Programs for Chemical Process Design, Analysis, and Simulation, Flashing and Cavitation. Choked flow produces either flashing or cavitation.
Flashing occurs when the pressure downstream of the valve is below the vapor pressure of the liquid, ΔP and internal valve erosion often occur because the velocity of flashing the vapor-liquid stream is higher.
proportionally constant being the specific heat. Due to different mathematical characters of governing equations for compressible and incompressible flows, CFD codes are usually written for only one of them.
It is not common to find a code that can effectively and accurately work in both compressible and incompressible flow regimes. The dynamic behavior of the vapor flow in heat pipes is investigated at startup and during operational transients.
The vapor is modeled as two-dimensional, compressible viscous flow in an enclosure with inflow and outflow boundary conditions.
For steady-state and operating transients.The effects of conjugate heat transfer, vapor compressibility, and viscous dissipation in heat pipes are discussed.
The accuracy of the partially parabolic versus the elliptic presentation of the governing equations is also examined. The results show that the axial wall conduction has a tendency to make the temperature distribution more uniform for heat pipes with large ratios of pipe wall to. The capabilities of HPTAM, a two‐dimensional Heat Pipe Transient Analysis Model, are extended to include modeling of free‐molecular and transition vapor flow regimes during the startup from either a frozen state or fully‐thawed condition of high‐temperature heat pipes.
The one‐dimensional transient vapor flow model developed herein is based on the Dusty Gas Model.