An Experimental Investigation of Pressure Drop During Partial Condensation of Low Pressure Steam

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Jacques du Plessis ◽  
Michael Owen
Keyword(s):  
Pressure Drop ◽  
Cooling System ◽  
Thermal Power ◽  
Steam Pressure ◽  
Tube Length ◽  
Condenser Tube ◽  
Cooling Systems ◽  
Frictional Pressure Drop ◽  
Wide Range ◽  
Experimental Apparatus

Abstract As direct dry-cooling systems are becoming more popular for thermal power plants, there is a demand to increase the flexibility of the application and performance of these cooling systems. A novel hybrid (dry/wet) dephlegmator (HDWD) cooling system is being developed, and at this stage in the development of the HDWD, the performance analysis and optimization of the HDWD is currently subject to uncertainties in a number of parameters. One of the parameters is the confidence in the correlations to predict the steam-side pressure drop over the wide range of full to partial condensation conditions expected in the system as a result of the design. This study makes use of an experimental apparatus to measure steam pressure drop over a range of partial to full condensation inside a circular horizontal tube. The experiment is conducted by measuring the steam flow and steam pressure drop in a horizontal primary condenser tube with the presence of a secondary condenser tube. The primary condenser has a tube length of 2.5 m and an inside tube diameter of 19.3 mm similar to the proposed HDWD design. Existing correlations for pressure drop in condensing flow are compared with the results to assess the applicability of the correlations for the HDWD case. It was found that the correlation of Lockhart and Martinelli’s with the Chisholm parameter fits the experimental data the best with a mean error of ±15.6%. A parametric study also indicated that there is a prominent increase in the frictional pressure drop at low partial condensation ratios (i.e., high steam through flow) as expected with wave drag at the vapor and condensate interface due to the difference in velocity.

Hydrodynamic Analysis of Direct Steam Generation Solar Collectors

1999 ◽  
Vol 122 (1) ◽  
pp. 14-22 ◽  
Author(s):  
S. D. Odeh ◽  
M. Behnia ◽  
G. L. Morrison
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Operating Conditions ◽  
Tube Length ◽  
Solar Collectors ◽  
Flow Conditions ◽  
Steam Generation ◽  
Frictional Pressure Drop ◽  
Wide Range ◽  
Direct Steam

Direct steam generation collectors are considered with the aim to improve the performance of a parabolic trough collector leading to a reduction of operating costs of solar electric generation systems. In this study a hydrodynamic steady state model is developed and linked with a thermal model to optimize the performance of once-through direct steam generation solar collectors. The hydrodynamic model includes flow pattern classification and a pressure drop model. Flow pattern maps for typical DSG collectors with horizontal and inclined absorber tubes are generated to investigate the variation of flow conditions with radiation level, tube diameter, tube length and flow rate. Two-phase flow frictional pressure drop correlations for the range of operating conditions in a DSG collector are selected from the wide range of published correlations by comparison with experimental data for typical steam-water flow conditions in a DSG collector. Pressure drop is calculated for different operating conditions for both horizontal and inclined solar absorber tubes. Alternative operational strategies are evaluated to achieve optimum performance of a direct steam generation collector at different radiation levels. [S0199-6231(00)00101-5]

An Improved Correlation for Two-Phase Frictional Pressure Drop in Boiling and Adiabatic Downflow in the Annular Flow Regime

1991 ◽  
Vol 205 (5) ◽  
pp. 317-328 ◽  
Author(s):  
J F Klausner ◽  
B T Chao ◽  
S L Soo
Keyword(s):  
Pressure Drop ◽  
Film Thickness ◽  
Flow Regime ◽  
Annular Flow ◽  
Volume Fraction ◽  
Interfacial Shear Stress ◽  
Published Data ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Wide Range

An improved correlation is presented for annular two-phase frictional pressure drop data for vertical downflow. An ideal dimensionless film thickness based on the vapour volume fraction, a characteristic friction factor based on the two-phase frictional pressure gradient and a Weber number relevant for the interfacial capillary wave structure are the correlating parameters. The proposed new correlating scheme is tested against a wide range of data obtained in this investigation for refrigerant R11 in forced convection boiling and in adiabatic test sections of 19 mm cylindrical cross-section as well as published data for air-water and air-glycerine solution mixtures in the annular flow regime. Over 80 per cent of the measured values fall within ±30 per cent of those predicted from the correlation. Due to the wide range of liquid film thickness covered, 0.05–2.9 mm, its validity extends past the range where previously reported downflow pressure drop correlations fail. A paradox connected with previously reported annular downflow pressure drop correlations based on the liquid-vapour interfacial shear stress is pointed out. Upflow frictional pressure drop data in the annular flow regime can also be correlated by the proposed scheme.

scholarly journals The Effect of Spool Displacement Control to the Flow Rate in the Piezoelectric Stack-Based Valve System Subjected to High Operating Temperature

Actuators ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 239
Author(s):  
Yu-Jin Park ◽  
Bo-Gyu Kim ◽  
Jun-Cheol Jeon ◽  
Dongsoo Jung ◽  
Seung-Bok Choi
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Operating Temperature ◽  
Control Volume ◽  
Tracking Error ◽  
Displacement Control ◽  
Structural Part ◽  
Valve System ◽  
Wide Range ◽  
Experimental Apparatus

This work investigates the effect of spool displacement control of the piezoelectric stack actuator (PSA) based valve system on the flow motion of the pressure drop and flow rate. As a first step, the governing equations of the structural parts of the displacement amplifier and spool are derived, followed by the governing equation of the fluid part considering control volume and steady flow force. Then, an appropriate size of the valve is designed and manufactured. An experimental apparatus to control the spool displacement is set up in the heat chamber and tracking control for the spool displacement is evaluated at 20 °C and 100 °C by implementing a proportional-integral-derivative (PID) feedback controller. The tracking controls of the spool displacement associated with the sinusoidal and triangular trajectories are realized at 20 °C and 100 °C. It is demonstrated that the tracking controls for the sinusoidal and triangular trajectories have been well carried out showing the tracking error less than 3 μm at both temperatures. In addition, the flow motions for the pressure drop and the flow rate of the proposed valve system are experimentally investigated. It is identified from this investigation that both pressure drop and flow rate evaluated 20 °C have been decreased up to 18% at 100 °C. This result directly indicates that the temperature effect to control performance of the structural part and fluid part in the proposed PSA based valve system is different and hence careful attention is required to achieve the successful development of advanced valve systems subjected to a wide range of the operating temperature.

scholarly journals Análisis térmico e hidráulico de diferentes geometrías de tubos para mejorar el desempeño de un radiador de automóvil

2020 ◽  
pp. 13-23
Author(s):  
José Luis ZUÑIGA-CERROBLANCO ◽  
Juan Gregorio HORTELANO-CAPETILLO ◽  
Juan Carlos COLLAZO-BARRIENTOS ◽  
Abel HERNANDEZ-GUERRERO
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Automotive Industry ◽  
New Technologies ◽  
Cooling System ◽  
Numerical Study ◽  
Hydraulic Performance ◽  
Cooling Systems ◽  
Cooling Fluid ◽  
Nusselt Numbers

Nowadays the automotive industry requires more powerful and compact engines, which demand that the cooling systems must be improved using new technologies to attend the aim to maintain the engine working at optimum temperature, the cooling system must be adjusted to the dimensions and weight set to avoid the increase of fuel expense. In the present work a numerical study to analyze the thermal and hydraulic performance of a car radiator is carried out. The research focuses on analyzing different geometries for the tubes that make up the radiator, inside of tubes a mixture of 80% water and 20% ethylene glycol is used as the cooling fluid. On the results the global Nusselt numbers for the different geometries, as well as the total pressure drop along the radiator tube are reported. A comparison of the thermal and hydraulic performance for the different geometries analyzed is made. From the results the best geometry to increase heat transfer is chosen, as well as the geometry with the best balance between entropy generation due to heat transfer and pressure drop is chosen.

EFFECT OF AMBIENT TEMPERATURE VARIATION ON PRESSURE DROP DURING CONDENSATION IN LONG INCLINED TUBES

2021 ◽  
pp. 1-24
Author(s):  
Kaipo Kekaula ◽  
Yitung Chen
Keyword(s):  
Pressure Drop ◽  
Ambient Temperature ◽  
Two Phase ◽  
Temperature Changes ◽  
Ambient Temperatures ◽  
Frictional Pressure Drop ◽  
Wide Range ◽  
Data Points ◽  
Fan Speed ◽  
Increasing Temperature

Abstract Two-phase flow pressure drop during condensation of steam inside inclined tube heat exchangers was investigated over a wide range of ambient temperature. The ambient temperature changes from 3 to 45°C, the steam mass flux varies from 3 to 18 kg/(m2·s), vapor quality ranges from 0.51 to 0.86. 608 data points were experimentally obtained and compared with 8 commonly used correlations from the available literatures. Frictional pressure drop increases with increasing temperature difference and fan speed. For the full experimental dataset, the best overall performing correlation was obtained by using the Wallis correlation (MAPE = 17.60%, NRMSE = 14.87%). For cold ambient temperatures, (Tamb < 20°C, N=298), the best overall performing correlation was obtained by using the Carey correlation (MAPE = 11.02%, NRMSE = 14.71%). For hot ambient temperatures (Tamb >30°C, N = 196), the Lockhart and Martinelli correlation has shown the best performance (MAPE = 16.84%, NRMSE = 20.45%). An improved two-phase frictional pressure drop correlation based on the Wallis correlation [21] is proposed.

Study of the opportunity of using technical water supply systems at Thermal Power Plants in accordance with the climatic conditions of Azerbaijan

2021 ◽  
Vol 65 (04) ◽  
pp. 244-248
Author(s):  
Nərmin Qaroğlan qızı Quliyeva ◽  
Keyword(s):  
Water Supply ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Power ◽  
Climatic Conditions ◽  
Water Supply Systems ◽  
Thermal Power Plants ◽  
Cooling Systems ◽  
Closed Systems ◽  
Supply Systems

Given that the required amount of technical water supply causes environmental problems and is one of the problems of global warming, as well as reducing the amount of water in rivers and water basins, we can achieve a more environmentally efficient cooling system by switching from traditional to closed indoor cooling systems of the thermal power plants. Thus we can use water more efficiently in accordance with climatic conditions. Key words: thermal power plants, closed systems, cooling systems, evaporation, technical water supply, cycle

The Air Cooled Condenser for Dry Countries

2006 ◽  
Author(s):  
Akbar Adibfar ◽  
Maryam Refan
Keyword(s):  
Power Plants ◽  
Cooling System ◽  
Thermal Power ◽  
Power Production ◽  
Water Shortage ◽  
Special Focus ◽  
Cooling Systems ◽  
Optimum Selection ◽  
Higher Power ◽  
Selection Of

A reliable and economic power production in thermal power plants depends highly upon the optimum selection of site equipment and their best possible arrangement. One of the most significant systems which play a crucial role in power production is the Cooling System. Playing the most pivotal role in back pressure of steam turbine, this system directly affects the power plant efficiency. This study analyzes the techno-economic aspect of Cooling System — with the special focus on ACC (Air Cooled Condenser) — due to the following advantages: Since ACC does not need water as the cooling medium, (not requiring medium fluid), it is been preferred over other cooling systems in dry regions. In addition to resolving the problem of water shortage in power plants, where there are environmental or geographical limitations, ACC is the best solution. The studies show that in the peak demand times, ACC has a much greater potential in higher power production in comparison to other dry cooling systems and thus can encourage the financer to consider ACC as an optimum alternative.

scholarly journals Influence of Selected Factors on Thermal Parameters of the Components of Forced Cooling Systems of Electronic Devices

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 340
Author(s):  
Krzysztof Posobkiewicz ◽  
Krzysztof Górecki
Keyword(s):  
Electronic Device ◽  
Cooling System ◽  
Electronic Devices ◽  
Heat Sinks ◽  
Cooling Systems ◽  
Peltier Module ◽  
Wide Range ◽  
Peltier Modules ◽  
Analytical Formulas ◽  
Forced Cooling

The paper presents some investigation results on the properties of forced cooling systems dedicated to electronic devices. Different structures of such systems, including Peltier modules, heat sinks, fans, and thermal interfaces, are considered. Compact thermal models of such systems are formulated. These models take into account a multipath heat transfer and make it possible to compute waveforms of the device’s internal temperature at selected values of the power dissipated in the device. The analytical formulas describing the dependences of the thermal resistance of electronic devices co-operating with the considered cooling systems on the power dissipated in the cooled electronic device and the power feeding the Peltier module and the speed of airflow caused by a fan are proposed. The correctness of the proposed models is verified experimentally in a wide range of powers dissipated in electronic devices operating in different configurations of the used cooling system.

Two-Phase Flow Regime Modeling and Pressure Drop Behavior

2007 ◽  
Author(s):  
Braden A. McDermott ◽  
Timothy A. Shedd
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Two Phase Flow ◽  
Current Data ◽  
Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Flow Maps ◽  
Mass Fluxes ◽  
Wide Range

A unique horizontal two-phase flow facility has been fabricated in an effort to understand the dynamics of two-phase flow in small pipes. The fluid chosen for study is the low pressure refrigerant R-123. In this work, two-phase pressure drop data were obtained for two-phase flow of refrigerant R-123 in a 17.0 mm inner diameter tube over a wide range of quality, from .015–1, and mass fluxes that were varied from 50 kg m−2 s−1 to 550 kg m−2 s−1. These data have been compared, as a whole and by regime, against four frequently-used two-phase frictional pressure drop prediction correlations. Flow regimes were visualized using a quartz tube at the end of the test section over this wide range of conditions, which ranged from stratified to annular flow. Each condition was mapped on the Mandhane, Taitel-Dukler, and Kattan-Favrat-Thome flow regime maps in an attempt to understand the applicability of each. Some discrepancies exist between the current data and the published flow maps, and recommendations are made based on these observations. The pressure drop data appear to be dependent upon the flow regime, suggesting that an entire set of correlations is necessary based upon flow regime for accurate prediction of pressure drop.

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