Closed Loop Two-Phase Thermosyphon of Small Dimensions: a Review of the Experimental Results

2011 ◽  
Vol 24 (3) ◽  
pp. 165-179 ◽  
Author(s):  
Alessandro Franco ◽  
Sauro Filippeschi
Keyword(s):  
Closed Loop ◽  
Experimental Results ◽  
Two Phase

Random Forces Resulting From Internal Two-Phase Flow on Bends and Tees

2006 ◽  
Author(s):  
E. de Langre ◽  
J. L. Riverin ◽  
M. J. Pettigrew
Keyword(s):  
Two Phase Flow ◽  
Experimental Results ◽  
Time Dependent ◽  
Phase Flow ◽  
Water Mixture ◽  
Dimensionless Form ◽  
Two Phase ◽  
Practical Applications ◽  
Random Forces

The time dependent forces resulting from a two-phase air-water mixture flowing in an elbow and a tee are measured. Their magnitudes as well as their spectral contents are analyzed. Comparison is made with previous experimental results on similar systems. For practical applications a dimensionless form is proposed to relate the characteristics of these forces to the parameters defining the flow and the geometry of the piping.

Evaporation of Single Drops of n-Pentane/n-Hexane Mixtures in Water

1992 ◽  
Vol 114 (4) ◽  
pp. 965-971 ◽  
Author(s):  
H. Shimaoka ◽  
Y. H. Mori
Keyword(s):  
Heat Transfer ◽  
Temperature Difference ◽  
Vapor Bubble ◽  
Experimental Results ◽  
Rise Velocity ◽  
Heat Transfer Characteristics ◽  
Two Phase ◽  
Transfer Characteristics ◽  
Preceding Work ◽  
Liquid Vapor

The evaporation of isolated drops (2.1−3.0 mm diameter) of nonazeotropic n-pentane/n-hexane mixtures in the medium of water was observed under pressures of 0.11−0.46 MPa and temperature differences up to 27 K. The mole fractions of n-pentane, x, in the mixtures were set at 0.9, 0.5, 0.1, and 0, to be completed by the condition x = 1 set in a preceding work (Shimaoka and Mori, 1990). Experimental results are presented in terms of the instantaneous rise velocity of, and an expression of instantaneous heat transfer to, each drop evaporating and thereby transforming into a liquid/vapor two-phase bubble and finally into a vapor bubble. The dependencies of the heat transfer characteristics on the pressure, the temperature difference, and x are discussed.

scholarly journals Shock Phenomena in a One-component Two-phase Bubbly Flow : 1st Report, Experimental Results on Transient Pressure Profiles

1986 ◽  
Vol 29 (258) ◽  
pp. 4235-4240
Author(s):  
Terushige FUJII ◽  
Koji AKAGAWA ◽  
Nobuyuki TAKENAKA ◽  
Sadao TSUBOKURA ◽  
Yoichi HIRAOKA ◽  
...  
Keyword(s):  
Bubbly Flow ◽  
Experimental Results ◽  
Transient Pressure ◽  
Two Phase ◽  
Pressure Profiles

Two-phase and single phase models of flow of nanofluid in a square cavity: Comparison with experimental results

2016 ◽  
Vol 100 ◽  
pp. 372-380 ◽  
Author(s):  
M. Ziad Saghir ◽  
Amirhossein Ahadi ◽  
Tooraj Yousefi ◽  
Bahram Farahbakhsh
Keyword(s):  
Single Phase ◽  
Experimental Results ◽  
Square Cavity ◽  
Two Phase ◽  
Phase Models

scholarly journals DQ-Frame Admittance Estimation of Three-Phase Converters with a Wide Range of Operating Points

2021 ◽  
Author(s):  
Hong Gong ◽  
xiongfei wang ◽  
Dongsheng Yang
Keyword(s):  
Error Estimation ◽  
Closed Loop ◽  
Estimation Method ◽  
Experimental Results ◽  
Multidimensional Interpolation ◽  
Three Phase ◽  
Wide Range ◽  
Linearized Model ◽  
Operating Points ◽  
Error Estimation Method

The <i>dq</i>-frame admittance of closed-loop controlled three-phase converters is a linearized model that is dependent on the operating points of the system. Yet, it is impractical to measure the converter admittance at all operating points. This paper, thus, proposes an approach to estimating the <i>dq</i>-frame admittance of three-phase converters at a wide range of operating points. The method applies multidimensional interpolation to a given set of admittance data, which is measured from the pre-defined operating points. The accuracy of interpolation is then evaluated by using the posterior error estimation method. The number of pre-defined operating points is next adjusted to find a good compromise between the accuracy and efficiency of the approach. Simulations and experimental results verify the effectiveness of the approach.<div><br></div>

A Natural Circulation Model of the Closed Loop, Two-Phase Thermosyphon for Electronics Cooling

2001 ◽  
Author(s):  
S. I. Haider ◽  
Yogendra K. Joshi ◽  
Wataru Nakayama
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Closed Loop ◽  
Two Phase Flow ◽  
Natural Circulation ◽  
Saturation Temperature ◽  
Electronics Cooling ◽  
Phase Flow ◽  
Two Phase

Abstract The study presents a model for the two-phase flow and heat transfer in the closed loop, two-phase thermosyphon (CLTPT) involving co-current natural circulation. Most available models deal with two-phase thermosyphons with counter-current circulation within a closed, vertical, wickless heat pipe. The present research focuses on CLTPTs for electronics cooling that face more complex two-phase flow patterns than the vertical heat pipes, due to closed loop geometry and smaller tube size. The present model is based on mass, momentum, and energy balances in the evaporator, rising tube, condenser, and the falling tube. The homogeneous two-phase flow model is used to evaluate the friction pressure drop of the two-phase flow imposed by the available gravitational head through the loop. The saturation temperature dictates both the chip temperature and the condenser heat rejection capacity. Thermodynamic constraints are applied to model the saturation temperature, which also depends upon the local heat transfer coefficient and the two-phase flow patterns inside the condenser. The boiling characteristics of the enhanced structure are used to predict the chip temperature. The model is compared with experimental data for dielectric working fluid PF-5060 and is in general agreement with the observed trends. The degradation of condensation heat transfer coefficient due to diminished vapor convective effects, and the presence of subcooled liquid in the condenser are expected to cause higher thermal resistance at low heat fluxes. The local condensation heat transfer coefficient is a major area of uncertainty.

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