scholarly journals Study of heat transfer during steam condensation in the tubes of diesel radiator cores

2021 ◽  
Vol 2131 (2) ◽  
pp. 022047
Author(s):  
Ya K Sklifus ◽  
O V Ignatieva
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Regression Equations ◽  
Steam Condensation ◽  
Diesel Locomotive ◽  
Standard Radiator ◽  
Working Length ◽  
Criterion Equation ◽  
Flat Tubes ◽  
The Mathematical Model

Abstract The article contains an assumption about the practicability of using the processes of boiling and condensation of the coolant in the cooling system of a locomotive diesel in order to reduce the energy consumption of fans of the refrigerating chamber. The possibility of using of standard radiator cores of a diesel locomotive with flat tubes as steam condensers is considered. The results of the criterion equation of heat transfer from steam to a flat tube during condensation, obtained by the mathematical model of this process, are estimated. The assessment was carried out by comparison with experimental data. The influence of the initial steam velocity, the corresponding tube diameter, the working length of the tube, the physical properties of steam and condensate is considered. The comparison of the influence of these factors on heat transfer in round and flat tubes of a locomotive radiator core is carried out. The processed results of physical and numerical experiments for both circular and flat tubes are shown in the graphs and regression equations. The advantage of flat tubes over round ones in terms of heat transfer intensity during steam condensation, which can reach 24%, for a standard radiator core of a diesel locomotive was found.

Experimental Research on Steam Condensation on Cold Surface: Facility Design

2014 ◽  
Author(s):  
Li-Yong Han ◽  
Lin Yang ◽  
Shan Zhou ◽  
Shen Wang ◽  
Chun-Lai Tian ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Test Section ◽  
Cooling System ◽  
Theoretical Research ◽  
Test Facility ◽  
Measurement Technology ◽  
Ambient Conditions ◽  
Steam Condensation ◽  
Cold Surface ◽  
Process Gas

The passive containment cooling system (PCCS) of the 3rd generation APWR utilizes natural phenomena to transfer the heat released from the reactor to the environment during postulated designed basic accidents. Steam condensation on the inner surface of the containment shell is one of the most dominate mechanism to keep the ambient conditions within the design limits. Extensive experiment and theoretical research shows condensation is a complex process, gas pressure, film temperature and velocity of the gas have impact on the heat transfer coefficient. To span the expected range of conditions and provide proper model for evaluating the condensation heat transfer process, SCOPE test facility was designed by State Nuclear Power Technology Research & Development Centre (SNPTRD) in various conditions anticipated the operating range of CAP1400 in accident conditions. Pressurized test section with a rectangular flowing channel was used, with one of the walls cooled to maintain low temperature for condensing, supplying systems was designed for different pressures, gas temperatures, velocities and coolant water temperatures. Facility components, test section structure, supplying systems and measurement technology were described in this paper, also results of some pre-tests was introduce to show property of the facility.

Experimental Study of Non-Condensable Effect on Passive Condenser System

2007 ◽  
Author(s):  
Wenzhong Zhou ◽  
Shripad T. Revankar
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Heat Removal ◽  
Scaling Analysis ◽  
Steam Condensation ◽  
Transfer Coefficients ◽  
Specific Design ◽  
Heat Transfer Coefficients ◽  
Removal Capacity ◽  
Safety Systems

One of the engineered safety systems in the advanced boiling water reactor is a passive containment cooling system (PCCS) which is composed of a number of vertical heat exchanger. A set of steam condensation experiments is conducted to evaluate the heat removal capacity of a PCCS condenser. A condensing tube is submerged in a water pool where condensation heat is transferred by secondary boiling heat transfer. The specific design of condensing tube is based on scaling analysis from the PCCS design of ESBWR. The two condensing tubes have same height (0.9m) but different inside diameters, 26.6mm and 52.5mm, respectively. Condensation heat transfer coefficients (HTC) are obtained under various test conditions, such as different primary pressure (150 – 450 kPa), inlet steam flow rate (1 – 5 g/s), air mass fraction (0 – 20%) and tube size (26.6 mm and 52.5 mm ID). The effects of these parameters to condensation performance are evaluated.

scholarly journals EXPERIMENTAL STUDIES OF HEAT EXCHANGE DURING WATER COOLING AND STEAM CONDENSATION IN DEMOVER RADIATOR SECTIONS

2021 ◽  
Vol 1 (38) ◽  
pp. 107-114
Author(s):  
V. Mogila ◽  
M. Kovtanets ◽  
M. Morneva
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Cooling System ◽  
Experimental Studies ◽  
Road Transport ◽  
Thermal Calculation ◽  
Mode Of Operation ◽  
Simulation Results ◽  
The Mathematical Model

The Department of Railwayand Road Transport, lift and care system of Volodymyr Dahl East Ukrainian National University, an energy-saving cooling system for diesel locomotives using phase transitions of the coolant has been developed. The proposed cooling system allows to maintain constant optimal temperatures of cooling objects at ambient temperatures ± 40 ºC and in any mode of operation of the diesel engine. For thermal calculation of the radiator section operating in the mode of the steam condenser, the mathematical model of process of heat transfer from steam to walls of a flat tube at condensation is developed that considers geometrical features of section of a tube. The adequacy of this mathematical model is verified by comparing the simulation results with the obtained experimental data. During the tests, the outlet water temperature, inlet and outlet air temperature, and air pressure in front of and behind the radiator were measured. Having the values of wall temperature, steam temperature and condensate, knowing the value of steam consumption and the experimental heat transfer coefficient, it becomes possible to verify the adequacy of the mathematical model by comparing the simulation results with the obtained experimental data. Schemes of bench equipment, test methods, experimental planning and basic calculation dependences required for testing serial radiator sections of a locomotive in the standard mode of operation and in the mode of steam condensers are presented.

Mathematical Model of Thermal Physics of the Dual-Cycle Cooling System of the Tool for Pieces Nanostructuring Burnishing

2015 ◽  
Vol 770 ◽  
pp. 449-455 ◽  
Author(s):  
Viktor P. Kuznetsov ◽  
Andrei S. Skorobogatov ◽  
V.G. Gorgots
Keyword(s):  
Mathematical Modeling ◽  
Heat Transfer ◽  
Mathematical Model ◽  
Cooling System ◽  
Heat Removal ◽  
System Of Equations ◽  
Thermal Physics ◽  
Nanostructuring Burnishing ◽  
Dual Cycle ◽  
The Mathematical Model

The article considers the problems of the mathematical modeling of thermal physics of the tool for nanostructuring burnishing. Physical and equivalent heat diagram of the system are developed. On the basis of the equivalent heat transfer diagram, the equivalent circuit and the system of equations of the mathematical model are created. The dependence of the tool indenter tip temperature on cooling system thermal parameters is obtained. The comparison of efficiency of heat removal from the tool indenter when using the developed two-circuit cooling system and the system supplying lubricant cooling liquid through the lathe centre spindle, as well as when applying nanostructuring burnishing without cooling is carried out.

An Experimental Investigation of Steam Condensation in the Presence of Non-Condensable Gases for Nuclear Plant Containment

2014 ◽  
Author(s):  
Jiqiang Su ◽  
Zhongning Sun ◽  
Yanmin Zhou ◽  
Chaoxing Yan ◽  
Guangzhan Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Fraction ◽  
Cooling System ◽  
Nuclear Reactors ◽  
Condensation Heat Transfer ◽  
Steam Condensation ◽  
Air Mass

The condensation heat transfer occurring in containment atmospheres during the loss of coolant accident (LOCA), is one of the most important areas in research related to the safety of nuclear reactors. In the advanced Generation III and III+ nuclear reactors, decay heat is removed by passive containment cooling system (PCCS). For the system, the study of condensation of steam in the presence of non-condensable gases is prior to be investigated because when LOCA happens steam flashes into the containment which contains air and other non-condensable gases (helium, argon, etc.). An experimental investigation has been conducted to evaluate the steam heat removal capacity over a vertical tube external surface with air. Condensation heat transfer coefficients have been obtained under the total pressure ranging from 0.4MPa to 0.6MPa, the wall subcooling ranging from 13 to 25°C and air mass fraction ranging from 0.07 to 0.52. The influence of the wall subcooling on the steam condensation heat transfer with the fixed pressure and air mass fraction have been researched. The effect of wall subcooling on condensation heat transfer coefficient with air is negative. The developed empirical correlation for the heat transfer coefficient covered all data points within 15%.

Multi-Dimensional Thermal-Hydraulic Analysis for Horizontal Tube Type PCCS

2002 ◽  
Author(s):  
Kenji Arai ◽  
Tomohisa Kurita ◽  
Mikihide Nakamaru ◽  
Yasunobu Fujiki ◽  
Hideo Nakamura ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Loss ◽  
Cooling System ◽  
Large Diameter ◽  
Heat Removal ◽  
Horizontal Tube ◽  
Steam Condensation ◽  
Heat Transfer Deterioration ◽  
Tube Type

A passive containment cooling system (PCCS) using a shell-and-tube type heat exchanger has been developed as a decay heat removal system following a severe accident. A horizontal heat exchanger has been studied for the PCCS heat exchanger since it has several advantages over a vertical large diameter tube heat exchanger that was originally proposed for the SBWR. Based on the fundamental thermal-hydraulic test using a single horizontal U-tube, the feasibility of the horizontal tube type PCCS has been confirmed, and the analysis models for the steam condensation heat transfer with a non-condensable and the pressure loss with steam condensation have been established. In addition, the criterion for the film dryout type heat transfer deterioration in the boiling side has been clarified in the test. The heat exchanger performance is affected by the multi-dimensional thermal-hydraulic behavior in the cooling water pool and the interactions among the multiple heat transfer tubes. In order to clarify the multi-dimensional behavior, numerical analyses have been conducted employing a two-fluid model. From the analyses results, it has been confirmed that the horizontal PCCS heat exchanger meets the design requirements for both the heat removal and the pressure loss and there would be no film dryout type heat transfer deterioration occurred in the cooling pool.

Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

2012 ◽  
Vol 9 (1) ◽  
pp. 131-135
Author(s):  
M.A. Pakhomov
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Liquid Flow ◽  
Bubble Diameter ◽  
Gas Content ◽  
Two Phase ◽  
Eulerian Description ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow ◽  
The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

Heat Transfer Characteristics of Downward Facing Hot Horizontal Surfaces Using Mist Jet Impingement

2017 ◽  
Author(s):  
Ashutosh Kumar Yadav ◽  
Parantak Sharma ◽  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Vishal Nirgude ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Cooling System ◽  
Water Pressure ◽  
Jet Impingement ◽  
Surface Heat ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Impinging jet cooling technique has been widely used extensively in various industrial processes, namely, cooling and drying of films and papers, processing of metals and glasses, cooling of gas turbine blades and most recently cooling of various components of electronic devices. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. Controlled cooling, as an important procedure of thermal-mechanical control processing technology, is helpful to improve the microstructure and mechanical properties of steel. In industries for heat transfer efficiency and homogeneous cooling performance which usually requires a jet impingement with improved heat transfer capacity and controllability. It provides better cooling in comparison to air. Rapid quenching by water jet, sometimes, may lead to formation of cracks and poor ductility to the quenched surface. Spray and mist jet impingement offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronics industries. Mist jet impingement cooling of downward facing hot surface has not been extensively studied in the literature. The present experimental study analyzes the heat transfer characteristics a 0.15mm thick hot horizontal stainless steel (SS-304) foil using Internal mixing full cone (spray angle 20 deg) mist nozzle from the bottom side. Experiments have been performed for the varied range of water pressure (0.7–4.0 bar) and air pressure (0.4–5.8 bar). The effect of water and air inlet pressures, on the surface heat flux has been examined in this study. The maximum surface heat flux is achieved at stagnation point and is not affected by the change in nozzle to plate distance, Air and Water flow rates.

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