In the present paper the experiments for subcooled water flow and steam-water two-phase flow were conducted to investigate the effects of pulsation upon transient heat transfer characteristics in a closed-circulation ...
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An experiment has been conducted in detail to study the turbulent heat transfer in horizontal helically coiled tubes over a wide range of experimental parameters. We found that the enhancement of heat transfer in the ...
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The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow. To resolve this issue, us...
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The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow. To resolve this issue, using five parallel-wire conductance probes, time records of local liquid film thickness at five circumferential positions were collected. The characteristics of circumferential liquid film thickness profiles and its variation with gas and liquid velocities were obtained. The basic features of probability distribution function, probability density function, auto-correlation, cross-correlation and power spectrum density function of the disturbance waves in angular flow were studied respectively. The characteristics of circumferential profiles of disturbance waves and its variation with gas and liquid velocities were presented.
An experiment has been conducted in detail to study the turbulent heat transfer in horizontal helically coiled tubes over a wide range of experimental parameters. We found that the enhancement of heat transfer in the ...
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An experiment has been conducted in detail to study the turbulent heat transfer in horizontal helically coiled tubes over a wide range of experimental parameters. We found that the enhancement of heat transfer in the coils results from the effects of turbulent and secondary flows. With Reynolds number increasing to a high level, the contribution of the secondary flow becomes less to enhance heat transfer, and the average heat transfer coefficient of the coil is closer to that in straight tubes under the same conditions. The local heat transfer coefficients are not evenly distributed along both the tube axis and the periphery on the cross section. The local heat transfer coefficients on the outside are three or four times those on the inside, which is half of the average heat transfer. A correlation is proposed to describe the distribution of the heat transfer coefficients at a cross section. The average cross-section heat transfer coefficients are distributed along the tube axis. The average value at the outlet section should not be taken as the average heat transfer coefficient.
Three-sphase flow invo1ving oil-water two immiscible liquids and gas which is often foundin the fields of petroleum production has been studied in this paper.A new method with thecombination of a horizontal tube,a dow...
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Three-sphase flow invo1ving oil-water two immiscible liquids and gas which is often foundin the fields of petroleum production has been studied in this paper.A new method with thecombination of a horizontal tube,a downward flow vertica1 tube and an orifice to measure theflowrates is *** this method the frictional pressure drop in the downward vertical tube isreplaced by that in the horizontal tube,the void fraction is derived from the gravitational pressuredrop,then the volume fraction of the individual phase can also be *** individual flowratescan be calculated when the water fraction is *** method is applicable for many kinds ofoil-wells to measure the flowrates of crude oil,natural gas and *** with other methods,the presented method involves fewer measuring *** experimental results proved quitegood accuracy of the method,with measurement deviation within 10%,and reliable results wereobtained under high Dressure conditions.
The study of the interfacial waves is very important in understanding and grasping the laws of the phase interface exchange dynamics in gas-liquid two-phase flow. Based on a series of experiments and investigations, t...
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The study of the interfacial waves is very important in understanding and grasping the laws of the phase interface exchange dynamics in gas-liquid two-phase flow. Based on a series of experiments and investigations, the statistical characteristics of the interfacial waves in gas-liquid two-phase stratified flow in both time and frequency domains are presented. The statistical parameters with variations of the gas and liquid superficial velocities are analyzed and discussed.
With the gas exchange between the Taylor bubble and the following liquid slug taken into consideration a physically-based hydrodynamic model has been developed for gas-liquid slug flow in vertical and inclined tubes, ...
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With the gas exchange between the Taylor bubble and the following liquid slug taken into consideration a physically-based hydrodynamic model has been developed for gas-liquid slug flow in vertical and inclined tubes, which can predict the flow characteristics of slug flow in vertical and inclined tubes. Some experimental data arc obtained to check the model. In comparison with previously published results, the prediction by this model is better and in good agreement with the experimental data.
Helical tube is one type of once-through stream generators in integrative nuclear device. The thermal-hydrodynamic instabilities in helical tubes of a once-through steam generator (HTOTSG) with exit-steam superheated ...
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Helical tube is one type of once-through stream generators in integrative nuclear device. The thermal-hydrodynamic instabilities in helical tubes of a once-through steam generator (HTOTSG) with exit-steam superheated were studied by using multi-variable liner-frequency-domain theory. Based on the drift-flux model, a small perturbation method, as well as Laplace transformation theory, was empolyed to linearize the system of partial differential equations. A computer code called HTOTSGM-D was developed to investigate the influences of inlet flow rate, inlet subcooling, heat flux, and system pressure on oscillations. The calculated results showed that the above factors must be considered comprehensively in once-through steam generator design and operation, even though the installation of the entrance throttles was still an effective way to stabilize the system.
This paper discusses thermo-conductive plastic finned tube radiators used in water saving type powerstations. First, the development of thermo-conductive plastics is introduced. Second, in order todetermine the ration...
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This paper discusses thermo-conductive plastic finned tube radiators used in water saving type powerstations. First, the development of thermo-conductive plastics is introduced. Second, in order todetermine the rational geometric dimensions of thermo-conductive plastic finned tubes, an objectivefunction which takes the minimum volume of the consumed material for making finned tubes as an ob-ject is introduced. On the basis of the function, the economy comparison between thermaxonductiveplastic finned tubes and metal finned tubes is conducted.
Experimental investigation was carried out for gas-liquid slug flow in vertical and inclined tubes. The non- Invasive measurements of the gas-liquid slug flow were taken by using the EKTAPRO 1000 High Speed Motion Ana...
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