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Gulden G. Gunerhan - One of the best experts on this subject based on the ideXlab platform.
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UPSTREAM REBOILER DESIGN AND TESTING FOR REMOVAL OF Noncondensable Gases FROM GEOTHERMAL STEAM AT KIZILDERE GEOTHERMAL POWER PLANT, TURKEY
2000Co-Authors: Gulden G. Gunerhan, Glenn CouryAbstract:The Kizildere geothermal power plant in Turkey is a unique geothermal power plant with an installed capacity of 20.4 MWe. The most significant characteristic of the field is the high level of Noncondensable Gases (NCG’s), in amounts as high as 1020% (with an average of 13% at the inlet of the turbine) by weight of steam. The NCGs are being extracted from the condenser by gas compressors that consume about 18.3% of the total power production of the plant. An upstream reboiler process is another approach to remove the NCG’s from geothermal steam before they enter the turbine. Upstream reboilers therefore provide a cleaner and less corrosive steam supply to the turbine and condenser, increasing power generation performance for very high NCG content. In this paper, upstream reboiler systems are investigated as an alternative to conventional gas extraction systems for Kizildere geothermal power plant. Both vertical tube and direct contact type reboilers have been designed and evaluated. The direct contact type is being tested at the Kizildere field and is covered in this paper since the vertical tube type has been reported upon and tested extensively in the past. The direct contact tests have been carried out in the field with a gas removal efficiency 76.3±22.6% at the base case.
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An upstream reboiler design for removal of Noncondensable Gases from geothermal steam for Kizildere geothermal power plant, Turkey
Geothermics, 1999Co-Authors: Gulden G. GunerhanAbstract:Abstract Kizildere geothermal power plant, Turkey, has an installed capacity of 20.4 MW e . The field contains a high level of Noncondensable Gases (NCGs), changing from well to well, in amounts as high as 10–20% (with an average of 13% at the inlet of the turbine) by weight of steam. This amount of NCGs is being extracted from the condenser by gas compressors that consume about 17% of the total power production of the plant. An upstream reboiler process could be adopted to remove the NCGs from geothermal steam before they enter the turbine. Upstream reboilers therefore provide a cleaner and less corrosive steam supply to the turbine and condenser, increasing power generation performance for very high NCG contents. In this paper, upstream reboiler systems are investigated as an alternative to conventional gas extraction systems for Kizildere geothermal power plant. A vertical tube type reboiler has been designed and it is found that, as NCG content increases, the condensation heat transfer coefficient reduces steeply. It is concluded that vertical tube type reboilers are not efficient for fields that contain high levels of NCG (>15% by weight of steam). It is recommended that the use of direct contact reboilers be further investigated for this application.
A Naviglio - One of the best experts on this subject based on the ideXlab platform.
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film condensation in inclined tubes with Noncondensable Gases an experimental study on the local heat transfer coefficient
International Communications in Heat and Mass Transfer, 2013Co-Authors: Gianfranco Caruso, Damiano Vitale Di Maio, A NaviglioAbstract:Abstract An experimental investigation on the role of Noncondensable Gases during condensation of steam inside inclined tubes is presented. In a condenser, Noncondensable Gases flowing with steam cause reduction of condenser performance and efficiency. Many researchers have investigated in-tube condensation for vertical heat exchangers, but very few works have been performed to study condensation in inclined tubes with Noncondensable Gases. In the paper, experiments dedicated to this situation are described, with reference to the following conditions: tube internal diameter: 12.6 mm, 20 mm and 26.8 mm; tube inclination: 7°, 15°, 30° and 45°; inlet Noncondensable gas mass fraction ωin = 2%–42%; inlet mixture Reynolds number Rem,in = 5000–20000; local Noncondensable gas mass fraction ω = 2%–70%; local mixture Reynolds number Rem = 400–21000; local condensate Reynolds number Rel = 10–290; saturated steam at atmospheric pressure; and gravity controlled flow regime. A limited influence of the inclination angle on heat transfer coefficient has been observed. Correlations to evaluate the local heat transfer coefficient along inclined tubes, in a gravity controlled flow regime, have been developed and they are in good agreement with the experimental results.
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condensation heat transfer coefficient with Noncondensable Gases inside near horizontal tubes
Desalination, 2013Co-Authors: Gianfranco Caruso, Damiano Vitale Di Maio, A NaviglioAbstract:Abstract An experimental investigation on the role of Noncondensable Gases during condensation of steam inside horizontal/slightly inclined tubes is presented. In a condenser of a thermal desalination unit, the Noncondensable Gases flowing within the gas phase cause reduction of performance and efficiency. Many researchers have investigated in-tube condensation for horizontal heat exchangers, but very few works have been performed to study the condensation in slightly inclined tubes with Noncondensable Gases. Inclination of tubes may be requested to achieve suitable and reliable draining. Experiments were conducted in the following conditions: tube internal diameter 12.6 mm, 20 mm and 26.8 mm; tube inclination 7°; inlet Noncondensable gas mass fraction ωin = 5%–42%; inlet mixture Reynolds number Rem,in = 5000–20,000; local Noncondensable gas mass fraction ωin = 5%–60%; local mixture Reynolds number Rem = 500–20,000; saturated steam at atmospheric pressure, gravity controlled with stratified flow regime, in which the condensate is collected mainly in the bottom part of the tube due to gravity and it is drawn out by its own momentum. A correlation of mixed gas heat transfer coefficient along a slightly inclined tube, in a gravity controlled flow regime, has been developed, showing a good agreement with experimental results.
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Film condensation in inclined tubes with Noncondensable Gases: An experimental study on the local heat transfer coefficient
'Elsevier BV', 2013Co-Authors: Gianfranco Caruso, Damiano Vitale Di Maio, A NaviglioAbstract:An experimental investigation on the role of Noncondensable Gases during condensation of steam inside inclined tubes is presented. In a condenser, Noncondensable Gases flowing with steam cause reduction of condenser performance and efficiency. Many researchers have investigated in-tube condensation for vertical heat exchangers, but very few works have been performed to study condensation in inclined tubes with Noncondensable Gases. In the paper, experiments dedicated to this situation are described, with reference to the following conditions: tube internal diameter: 12.6 mm, 20 mm and 26.8 mm; tube inclination: 7 degrees, 15 degrees, 30 degrees and 45 degrees; inlet Noncondensable gas mass fraction omega(in) = 2%-42%; inlet mixture Reynolds number Re-m,Re-in = 5000-20000; local Noncondensable gas mass fraction omega = 2%-70%; local mixture Reynolds number Re-m = 400-21000; local condensate Reynolds number Re-l = 10-290; saturated steam at atmospheric pressure; and gravity controlled flow regime. A limited influence of the inclination angle on heat transfer coefficient has been observed. Correlations to evaluate the local heat transfer coefficient along inclined tubes, in a gravity controlled flow regime, have been developed and they are in good agreement with the experimental results. (C) 2013 Elsevier Ltd. All rights reserved
O. O. Milman - One of the best experts on this subject based on the ideXlab platform.
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Design and layout characteristics of steam turbine condensers
Thermal Engineering, 2014Co-Authors: V. A. Fedorov, O. O. MilmanAbstract:We present the results of investigations carried out during the development of steam turbine condensing systems comprising a condenser, an air removing device, and condensate and circulation systems. It is found that the tube bundle layout and the characteristics of devices for removing Noncondensable Gases have an essential effect on the heat transfer intensity and pressure in the condensers. The design of the heat-transfer surface of a condenser operating with constant velocity of steam during its condensation is described, and the procedure for calculating the area and configuration of such heat-transfer surface is outlined. Results from tests of such apparatuses are presented. It is shown that the heat-transfer coefficients in them are a factor of 1.5–3.0 higher than those in the existing condensers at a moderate velocity of cooling medium. A qualitative pattern of a change in the volume filled with Noncondensable Gases that occurs during a decrease of thermal load or drop of cooling medium temperature is shown taking as an example condensers with steam flowing inside the condenser tubes.
Gianfranco Caruso - One of the best experts on this subject based on the ideXlab platform.
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heat and mass transfer analogy applied to condensation in the presence of Noncondensable Gases inside inclined tubes
International Journal of Heat and Mass Transfer, 2014Co-Authors: Gianfranco Caruso, Damiano Vitale Di MaioAbstract:Abstract A theoretical and experimental investigation on steam condensation in presence of Noncondensable Gases within horizontal and inclined tubes is summarized in the present paper. A simple correlation mainly based on dimensionless numbers was derived and compared with previous formulations based on the diffusion layer model. The Noncondensable Gases presence during condensation is an important issue affecting the whole thermodynamic efficiency of the process, and for this reason highly investigated by many researchers. The experimental data obtained for condensation, inside horizontal or inclined tube (15°, 30° and 45°) with an internal diameter of 22 mm, of an air/steam mixture, at low mixture Reynolds numbers (
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film condensation in inclined tubes with Noncondensable Gases an experimental study on the local heat transfer coefficient
International Communications in Heat and Mass Transfer, 2013Co-Authors: Gianfranco Caruso, Damiano Vitale Di Maio, A NaviglioAbstract:Abstract An experimental investigation on the role of Noncondensable Gases during condensation of steam inside inclined tubes is presented. In a condenser, Noncondensable Gases flowing with steam cause reduction of condenser performance and efficiency. Many researchers have investigated in-tube condensation for vertical heat exchangers, but very few works have been performed to study condensation in inclined tubes with Noncondensable Gases. In the paper, experiments dedicated to this situation are described, with reference to the following conditions: tube internal diameter: 12.6 mm, 20 mm and 26.8 mm; tube inclination: 7°, 15°, 30° and 45°; inlet Noncondensable gas mass fraction ωin = 2%–42%; inlet mixture Reynolds number Rem,in = 5000–20000; local Noncondensable gas mass fraction ω = 2%–70%; local mixture Reynolds number Rem = 400–21000; local condensate Reynolds number Rel = 10–290; saturated steam at atmospheric pressure; and gravity controlled flow regime. A limited influence of the inclination angle on heat transfer coefficient has been observed. Correlations to evaluate the local heat transfer coefficient along inclined tubes, in a gravity controlled flow regime, have been developed and they are in good agreement with the experimental results.
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condensation heat transfer coefficient with Noncondensable Gases inside near horizontal tubes
Desalination, 2013Co-Authors: Gianfranco Caruso, Damiano Vitale Di Maio, A NaviglioAbstract:Abstract An experimental investigation on the role of Noncondensable Gases during condensation of steam inside horizontal/slightly inclined tubes is presented. In a condenser of a thermal desalination unit, the Noncondensable Gases flowing within the gas phase cause reduction of performance and efficiency. Many researchers have investigated in-tube condensation for horizontal heat exchangers, but very few works have been performed to study the condensation in slightly inclined tubes with Noncondensable Gases. Inclination of tubes may be requested to achieve suitable and reliable draining. Experiments were conducted in the following conditions: tube internal diameter 12.6 mm, 20 mm and 26.8 mm; tube inclination 7°; inlet Noncondensable gas mass fraction ωin = 5%–42%; inlet mixture Reynolds number Rem,in = 5000–20,000; local Noncondensable gas mass fraction ωin = 5%–60%; local mixture Reynolds number Rem = 500–20,000; saturated steam at atmospheric pressure, gravity controlled with stratified flow regime, in which the condensate is collected mainly in the bottom part of the tube due to gravity and it is drawn out by its own momentum. A correlation of mixed gas heat transfer coefficient along a slightly inclined tube, in a gravity controlled flow regime, has been developed, showing a good agreement with experimental results.
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Film condensation in inclined tubes with Noncondensable Gases: An experimental study on the local heat transfer coefficient
'Elsevier BV', 2013Co-Authors: Gianfranco Caruso, Damiano Vitale Di Maio, A NaviglioAbstract:An experimental investigation on the role of Noncondensable Gases during condensation of steam inside inclined tubes is presented. In a condenser, Noncondensable Gases flowing with steam cause reduction of condenser performance and efficiency. Many researchers have investigated in-tube condensation for vertical heat exchangers, but very few works have been performed to study condensation in inclined tubes with Noncondensable Gases. In the paper, experiments dedicated to this situation are described, with reference to the following conditions: tube internal diameter: 12.6 mm, 20 mm and 26.8 mm; tube inclination: 7 degrees, 15 degrees, 30 degrees and 45 degrees; inlet Noncondensable gas mass fraction omega(in) = 2%-42%; inlet mixture Reynolds number Re-m,Re-in = 5000-20000; local Noncondensable gas mass fraction omega = 2%-70%; local mixture Reynolds number Re-m = 400-21000; local condensate Reynolds number Re-l = 10-290; saturated steam at atmospheric pressure; and gravity controlled flow regime. A limited influence of the inclination angle on heat transfer coefficient has been observed. Correlations to evaluate the local heat transfer coefficient along inclined tubes, in a gravity controlled flow regime, have been developed and they are in good agreement with the experimental results. (C) 2013 Elsevier Ltd. All rights reserved
Zhongning Sun - One of the best experts on this subject based on the ideXlab platform.
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Forced convection condensation of steam in the presence of multicomponent Noncondensable Gases inside a horizontal tube
International Journal of Heat and Mass Transfer, 2017Co-Authors: Zhongning SunAbstract:Abstract An experimental investigation on condensation heat transfer characteristics of steam in the presence of multicomponent Noncondensable Gases in a horizontal tube is conducted in the present research. The experimental runs are carried out at a volume ratio of helium and Noncondensable Gases varying from 0% to 90%, the mixture Gases pressure between 0.13 and 0.2 MPa, over the mixture Gases velocity changing from 8 to 34 m/s, covering all the major flow patterns inside a pipe. The effects of inner wall subcooling, mixture Gases velocity and pressure on local heat transfer coefficient have been analyzed for annular, wavy and stratified flow. The change of the condensation heat transfer capacity for different volume ratios of helium in the Noncondensable Gases have been studied at the same time. The results indicate that the local heat transfer coefficient increases with the increasing wall subcooling for annular and wavy flow but decreases for stratified flow. With the flow regime transforming from annular to stratified flow, the active influence of the Gases velocity is gradually weakened and the local heat transfer coefficient even starts to decrease when it reaches stratified flow. For all flow patterns, the increases of helium volume fraction and mixture Gases pressure always enhance the condensation heat transfer. Based on the experimental analysis, an empirical correlation for predicting the local heat transfer coefficient is proposed. The comparison of the calculated results and the experimental data shows that the present correlation can give satisfactory engineering accuracy.
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Influence of Wall Sub-Cooling on Local Heat Transfer for Forced Convection Condensation of Steam/Air in a Horizontal Tube
Volume 3: Thermal-Hydraulics, 2016Co-Authors: Qiunan Sun, Xiaofan Hou, Zhongning SunAbstract:For the purpose of analyzing the influence of wall sub-cooling on condensation heat transfer characteristic in the presence of Noncondensable Gases inside a horizontal tube, experiments for air-cooling and water-cooling at the secondary side outside the condenser tube have been conducted. By comparing the experimental data of different inlet air mass fraction, mixture Gases velocity and coolant volume flow rate, the variation of local heat transfer coefficient with wall sub-cooling was obtained. The results show that for annular and wavy flow, the condensation heat transfer coefficient increases with increasing wall sub-cooling but decreases for stratified flow. For annular and wavy flow, the positive influence of wall sub-cooling on condensation heat transfer coefficient is enhanced by the rise of inlet Noncondensable gas mass fraction, mixture Gases velocity and pressure.
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Experimental study on the effect of wall-subcooling on condensation heat transfer in the presence of Noncondensable Gases in a horizontal tube
Annals of Nuclear Energy, 2016Co-Authors: Zhongning SunAbstract:Abstract For the purpose of analyzing the influence of wall sub-cooling on condensation heat transfer characteristic in the presence of Noncondensable Gases inside a horizontal tube, experiments for air-cooling and water-cooling at the secondary side outside the condenser tube have been conducted. By comparing the experimental data of different inlet air mass fractions, mixture Gases velocities and coolant volume flow rates, the variation of local heat transfer coefficients with wall sub-cooling was obtained. The results show that for annular and wavy flow, the condensation heat transfer coefficient increases with the increasing wall sub-cooling but decreases for stratified flow. For annular and wavy flow, the positive influence of wall sub-cooling on condensation heat transfer coefficient is enhanced by the rise of inlet Noncondensable gas mass fraction, mixture Gases velocity and pressure. Finally, the modified correlations respectively for annular-wavy flow and stratified flow have been proposed which show a good agreement with the experimental data.
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Analysis of experiments for the effect of Noncondensable Gases on steam condensation over a vertical tube external surface under low wall subcooling
Nuclear Engineering and Design, 2014Co-Authors: Zhongning Sun, Ming Ding, Guangming FanAbstract:Abstract Experimental investigations have been conducted to study the steam heat removal capacity with Noncondensable Gases (e.g. air, helium) under low wall subcooling over a vertical tube external surface. The effect of the wall subcooling on the steam condensation heat transfer coefficients has been researched by experiments when the pressure and the air mass fractions are stable. At the air/steam cases, condensation heat transfer coefficient has been obtained under the wall subcooling degree ranging from13 to 25 °C, total pressure ranging from 0.4 MPa to 0.6 MPa and air mass fraction ranging from 0.07 to 0.52. Under the same pressure and Noncondensable Gases mass fraction, the effect of wall subcooling on condensation heat transfer coefficient with Noncondensable Gases is stronger than that with pure steam. The empirical correlation is developed for the heat transfer coefficient which covered all data points within 15%. Under air/helium/steam cases, the effect of helium (simulating hydrogen) on the heat transfer coefficient is investigated under the wall subcooling degree ranging from 18 to 27 °C, total pressure ranging from 0.53 MPa to 0.6 MPa, steam mass fraction ranging from 0.6 to 0.92 and helium volume fraction in Noncondensable Gases keeping 0.3. None of the experimental conditions is found the helium stratification. The condensation heat transfer coefficient that got from steam/air/helium condition is about 20% lower than that got from air/steam cases.