Effects of Tube Diameter, Length and Tube Numbers on Condensation of Steam in Vertical Tube Condenser

2009 ◽  
Author(s):  
Shripad T. Revankar ◽  
Gavin Henderson
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Tube Bundle ◽  
Vertical Tube ◽  
Tube Diameter ◽  
Condensation Heat Transfer ◽  
Steam Flow ◽  
Operating Pressure ◽  
Single Tube ◽  
Steam Flow Rate

A heat and mass analogy study was performed for the steam condensation in a vertical tube where steam is completely condensed. In the analysis a single tube, tube bundle with four tubes and two different diameter tubes were considered. The two condensing tubes of same height (0.9m) but different inside diameters, 26.6mm and 52.5mm, were used whereas the tube bundle was made of four tubes of height 1.8 m and 52.5 mm diameter. The results showed that the operating pressure is uniquely determined by inlet steam flow rate for the complete condensation. The condensation heat transfer rate increases and the condensation heat transfer coefficient decreases with the system pressure. The condensation heat transfer coefficients (HTC) were obtained as function various parameters such as different primary pressure (150–450 kPa) and inlet steam flow rate, single tube and tube bundle and tube diameters. Comparison with experimental condensation rates for single tube of 26.6 mm and 52.5 mm and four tube bundle of tube diameter 52.5 mm were made and the agreement was good. The effects of these parameters to condensation performance were evaluated.

Condensation in a Vertical Tube Bundle Operating in Passive Condensation Mode

2009 ◽  
Author(s):  
Gavin Henderson ◽  
Wenzhong Zhou ◽  
Shripad T. Revankar
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Cooling System ◽  
Tube Bundle ◽  
Condensation Heat Transfer ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Single Tube ◽  
Heat Transfer Coefficients ◽  
Condensation Mode

Passive condenser systems are used in a number of industrial heat transfer systems. Passive containment cooling system (PCCS) which is composed of a number of vertical heat exchanger serves as an engineered safety system in an advanced boiling water reactor. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure. Experiments were designed to simulate the PCCS condensation with a tube bundle. Scaling analysis was performed to scale down the prototype PCCS with a tube bundle consisting of four tubes. The tubes in the bundle were of prototype height (1.8 m) and diameter (52.5 mm) and the operating conditions and boundary conditions such as the operating pressure, secondary cooling system were designed to represent prototype conditions. Steam condensation tests were carried out in complete condensation mode where all the steam entering the condenser bundle is completely condensed. Condensation heat transfer coefficients (HTC) were obtained for various steam flow rate. The condensation pressure depended on the inlet steam flow rate which happens to be the maximum condensation rate for the given test pressure. Data on condensation heat transfer were obtained for primary pressure raging from 110–270 kPa. The tube bundle condensation heat transfer rates were compared with single tube heat transfer rates from previous work. The results showed that the condensation heat transfer coefficient for the tube in bundle was comparable with single tube, however the secondary side heat transfer coefficients for the tubes in bundle was higher than for the single tube. Condensation heat transfer for tube in bundle ranged from 7500 W/ m2K to 20,000 W/ m2K for the range of pressure studied. A heat and mass analogy model was developed and the condensation heat transfer prediction from the model was compared with experimental data.

Heat Transfer Characteristics of Passive Condensers for Reactor Containment Cooling

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Shripad T. Revankar
Keyword(s):  
Heat Transfer ◽  
Turbulent Mixing ◽  
Tube Bundle ◽  
Flow Boiling ◽  
Heat Removal ◽  
Theoretical Models ◽  
Outer Wall ◽  
Vertical Tube ◽  
Condensation Heat Transfer ◽  
Single Tube

Passive condensers that are based on gravitational force do not require pumps or blowers to move fluid and, hence, are considered as safety measures in nuclear power plant containment cooling. In this paper vertical tube passive condensers with the tube inside condensation and cooled by a secondary pool of water are discussed as applied to reactor containment heat removal system. Series of experiments were carried out on scaled separate effects test facilities with vertical single tube and four tube bundle condensers. The results of experimental data on the rate of condensation heat transfer, the effects of noncondensable, and parametric effects, such as pressure, tube diameters and lengths, obtained from single tube and tube bundle passive condenser are presented. The data on the tube bundle indicated larger condensation heat transfer due to enhanced heat transfer in the secondary cooling. For tube bundle condensation, the turbulent mixing on the secondary pool side decreases the temperature difference between pool water and condenser tube outer wall, causing an increase in secondary heat transfer. Theoretical models on tube condensation based on heat and mass analogy and boundary layer models were developed. The data were compared with theoretical models and good agreement was observed between theoretical predictions and single tube condensation heat transfer data. For the tube bundle condenser, the theoretical model agreed with data when the secondary side enhancement in heat transfer due to turbulent mixing in the flow boiling was included. Practical heat transfer correlations are presented using available data on passive condensers for reactor application.

Measurement and Modeling of Condensation Heat Transfer Coefficients in Circular Microchannels

2006 ◽  
Vol 128 (10) ◽  
pp. 1050-1059 ◽  
Author(s):  
Todd M. Bandhauer ◽  
Akhil Agarwal ◽  
Srinivas Garimella
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Heat Transfer Model ◽  
Condensation Heat Transfer ◽  
Low Flow ◽  
Transfer Model ◽  
Shear Stresses ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Circular Microchannels

A model for predicting heat transfer during condensation of refrigerant R134a in horizontal microchannels is presented. The thermal amplification technique is used to measure condensation heat transfer coefficients accurately over small increments of refrigerant quality across the vapor-liquid dome (0<x<1). A combination of a high flow rate closed loop primary coolant and a low flow rate open loop secondary coolant ensures the accurate measurement of the small heat duties in these microchannels and the deduction of condensation heat transfer coefficients from measured UA values. Measurements were conducted for three circular microchannels (0.506<Dh<1.524mm) over the mass flux range 150<G<750kg∕m2s. Results from previous work by the authors on condensation flow mechanisms in microchannel geometries were used to interpret the results based on the applicable flow regimes. The heat transfer model is based on the approach originally developed by Traviss, D. P., Rohsenow, W. M., and Baron, A. B., 1973, “Forced-Convection Condensation Inside Tubes: A Heat Transfer Equation For Condenser Design,” ASHRAE Trans., 79(1), pp. 157–165 and Moser, K. W., Webb, R. L., and Na, B., 1998, “A New Equivalent Reynolds Number Model for Condensation in Smooth Tubes,” ASME, J. Heat Transfer, 120(2), pp. 410–417. The multiple-flow-regime model of Garimella, S., Agarwal, A., and Killion, J. D., 2005, “Condensation Pressure Drop in Circular Microchannels,” Heat Transfer Eng., 26(3), pp. 1–8 for predicting condensation pressure drops in microchannels is used to predict the pertinent interfacial shear stresses required in this heat transfer model. The resulting heat transfer model predicts 86% of the data within ±20%.

A Novel Hybrid Method Based on Three-Stage Extraction and DEA-CCR Models for Selecting the Optimal Conditions for Citronella Oil Extraction

2021 ◽  
Author(s):  
Thaithat Sudsuansee ◽  
Narong Wichapa ◽  
Amin Lawong ◽  
Nuanchai Khotsaeng
Keyword(s):  
Energy Consumption ◽  
Flow Rate ◽  
Energy Cost ◽  
Oil Extraction ◽  
Steam Flow ◽  
Oil Yield ◽  
Steam Flow Rate ◽  
Citronella Oil ◽  
Extraction Model ◽  
Ccr Model

In citronella oil extraction process by steam distillation, inefficient use of steam is the main cause of excessive energy consumption that affects energy cost and oil yield. This research is aimed to reduce the energy cost and increase the oil yield by studying the steam used in the process. The proposed method is the three-stage extraction model combined with the Data Envelopment Analysis developed by Charnes, Cooper and Rhodes (DEA-CCR model). Although the three-stage extraction model has been widely used, there is no research integrate this model with DEA-CCR model. It is well known that DEA-CCR model is an effective tool to evaluate efficiency of decision making units/alternatives. The advantages of this research were presented as the calculation of the optimum distillation conditions, including the steam flow rate and the distillation time, were achieved as discussed in this article. The study was comprised of 3 parts. Firstly, the three-stage extraction model for citronella oil was formulated. Secondly, the results of the proposed model were calculated under different conditions, classified by steam flow rates from 5,000 to 60,000 cm3/min for the distillation period of 15–180 min. Finally, the DEA-CCR model was utilized to evaluate and rank alternatives. The results expressed that the best condition for producing citronella oil was at the steam flow rate of 40,000 cm3/min and the distillation time of 60 min. The optimal energy cost and percentage of oil yield were equal to 0.440 kWh/mL and 0.7%, respectively. When comparing to the experimental results, the percentage error of optimal energy cost and oil yield were slightly different, with a value of 0.98% and 0.85%, respectively. Moreover, the energy consumption was also reduced by 34.6% compared to the traditional operating conditions.

scholarly journals Condensation Heat Transfer Characteristics of R-1234yf with the Variation of Tube Diameter

2021 ◽  
Vol 41 (4) ◽  
pp. 161-171
Author(s):  
Sung-Hoon Seol ◽  
Jung-In Yoon ◽  
Joon-Hyuk Lee ◽  
Seung-Yun Cha ◽  
Su-Jeong Ha
Keyword(s):  
Heat Transfer ◽  
Tube Diameter ◽  
Condensation Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Effect of Adding Pump-Around Circuits and Reducing Stripping Steam Flow Rate on the Improving Energy Efficiency and Increasing Processing Capacity of the Atmospheric Column

2012 ◽  
Vol 550-553 ◽  
pp. 939-942
Author(s):  
Zhen Wang ◽  
Wei Wei Li ◽  
Hui Peng Zhao
Keyword(s):  
Energy Efficiency ◽  
Flow Rate ◽  
Steam Flow ◽  
Processing Capacity ◽  
Atmospheric Column ◽  
Steam Flow Rate ◽  
Refinery Plant ◽  
Stripping Steam

This paper discusses the effect of adding pump-around circuits and reducing stripping steam flow rate on the improving energy efficiency and increasing processing capacity of the atmospheric column in a refinery plant by using commercial simulator. It is shown that both the capacity and energy efficiency of the atmospheric column can be increased by adding pump-around circuits and reducing stripping steam flow rate. The modifications discussed in this paper will affect the separation of the atmospheric column in some way. However, the product qualities can still meet the specifications, if the changes of the parameters are not significant. Therefore, the above issues should be considered in the modifications overall.

Evaluation of Transmitted Ultrasonic Signal for Measuring Steam Flow Rate Using Clamp-on Ultrasonic Flowmeter

2019 ◽  
Vol 2019 (0) ◽  
pp. OS11-02
Author(s):  
Shuhei ICHIMURA ◽  
Hideki MURAKAWA ◽  
Katsumi SUGIMOTO ◽  
Shuichi UMEZAWA ◽  
Katsuhiko SUGITA
Keyword(s):  
Flow Rate ◽  
Ultrasonic Signal ◽  
Ultrasonic Flowmeter ◽  
Steam Flow ◽  
Steam Flow Rate

ICONE15-10619 CONDENSATION HEAT TRANSFER ON A VERTICAL TUBE UNDER NON-CONDENSABLE GAS CONDITION

2007 ◽  
Vol 2007.15 (0) ◽  
pp. _ICONE1510-_ICONE1510
Author(s):  
Masahiro Kawakubo ◽  
Hiroshige Kikura ◽  
Masanori Aritomi ◽  
Toshihiro Komeno
Keyword(s):  
Heat Transfer ◽  
Vertical Tube ◽  
Condensation Heat Transfer
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