Calculation and experimental analysis of heat transfer of assemblies of ribbed heat exchange elements

Abstract The results of thermal-hydraulic and strength tests of finned tube assemblies welded from KP 20 elements of four sizes are presented. The elements are representing by steel plate 0.4 mm in thickness, covered with a copper film 0.025 mm in thickness. One or two conical necks 17 mm long are extended in the plates. A set of placed in each other cones form a welded finned tube 23/20 mm with a toothed inner surface. As a result of the tests: high strength characteristics of these assemblies were demonstrated (internal pressure of burst under normal conditions is 40 MPa, resistance to sudden changes in temperature and freezing of water in “pipes”); a high average coefficient of thermal conductivity in the thickness of the ribs was confirmed at the level of 75 W/(m×K); the increase in the intensity of the heat transfer process is 2.15 times with the help of technological protrusions on the inner surface of the “pipe” to a turbulent single-phase flow in comparison with the calculated values for “smooth” pipes with a moderate increase in hydraulic resistance; the method of heat-hydraulic calculation of heat exchangers consisting of such “pipes” is proposed. The method is based on the ratios set out in the regulatory document “RD 24.035.05-89”. Thermal and hydraulic calculation of NPP heat exchanging equipment”, with amendments considering the high degree of finning of the tested “pipes” and the asymmetry of the edges of the ribs relative to the axis of the “pipes” bearing pressure, as well as the change in the value of the correction for the smallness of the tube bundle — we also identified areas of effective use of assemblies tested sizes of elements KP 20.

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The 3-D Numerical Simulation of Heat Transfer Process of Finned Copper Tube

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.393-395.412 ◽

2011 ◽

Vol 393-395 ◽

pp. 412-415

Author(s):

Jian Hua Zhong ◽

Li Ming Jiang ◽

Kai Feng

Keyword(s):

Heat Transfer ◽

Transfer Process ◽

Theoretical Calculations ◽

Structural Parameters ◽

Convection Heat Transfer ◽

Heat Transfer Process ◽

Finned Tube ◽

Copper Tube ◽

Central Air Conditioning ◽

Fin Thickness

In this article, finned copper tube used in the central air conditioning was acted as the discussed object. According to the combination with actual processing and theoretical calculations, Five finned tube was selected with typical structural parameters, and established their entity model using Pro/E, then the heat transfer process of finned tube was simulated through the ANSYS, the effect of the fin height, fin thickness and other structure parameters to the heat transfer enhancement of finned tube was researched. Meantime the efficiency of the heat transfer under different convection heat transfer coefficient was also studied.

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Shape and Size Optimization Design of Finned Brass Tube on the Central Air Conditioning

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.588-589.1854 ◽

2012 ◽

Vol 588-589 ◽

pp. 1854-1857

Author(s):

Shuang Chen ◽

Bing Yan Zhang ◽

Jian Hua Zhong

Keyword(s):

Heat Transfer ◽

Transfer Process ◽

Optimization Design ◽

Heat Transfer Process ◽

Finned Tube ◽

Structure Parameters ◽

Finite Element Program ◽

Fin Efficiency ◽

Heat Transfer Theory ◽

Element Program

Finned tube heat transfer process was analyzed in this thesis, the optimal mathematical model of the fin efficiency and fin volume which was acted as the objective function is established based on the model of heat transfer theory. The heat exchanger numerical simulation of finned tube is taken by the ANSYS finite element program in heat transfer process, and the finned tube structure parameters ( fin spacing , fin thickness , fin height) were analyzed , the optimum structure parameters of a set of finned tube were obtained at the same time. These studies will have some guidance on the application of finned tubes.

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Heat load of bimetallic ribbed tube

Proceedings of the Institute for System Programming of RAS ◽

10.15514//ispras-2021-33(5)-17 ◽

2021 ◽

Vol 33 (5) ◽

pp. 271-282

Author(s):

Elena Sergeevna Baimetova ◽

Albina Firdavesovna Gizzatullina ◽

Maria Ravilevna Koroleva ◽

Olga Vladimirovna Mishchenkova ◽

Fyodor Nikolaevich Pushkarev ◽

...

Keyword(s):

Heat Transfer ◽

Conjugate Heat Transfer ◽

Heat Removal ◽

Cylindrical Tube ◽

Longitudinal Section ◽

Heat Transfer Process ◽

Finned Tube ◽

Qualitative Comparison ◽

Bimetallic Finned Tube ◽

Metal Metal

This study is devoted to the problem of numerical modeling of the conjugate heat transfer in a closed-type power installation. The working elements of that are ribbed bimetallic tubes using the openFoam toolbox. The heat transfer process modeling in bimetallic tubes is associated with solving the problem of determining the value of the contact thermal resistance at the metal / metal interface. Considered design of a bimetallic tube involves crimping copper washers on the surface of an aluminum cylindrical tube. Hence, the contact surface of the tube is not isotropic in its properties. A mathematical model of conjugate heat transfer for air / bimetal / coolant medium is proposed. The features of the organization of thermophysical processes at the metal contact interface and at the metal / air and metal / coolant medium are shown. A qualitative comparison of the obtained results with the famous experimental data is carried out. Generalized temperature profiles in the rib longitudinal section are obtained by mathematical modeling. The given distributions of temperature and heat flux make it possible to estimate the contribution of each individual rib to the investigated heat removal process from the air environment. The efficiency of the considered technology of manufacturing a bimetallic finned tube is shown.

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Simplified analysis of heat transfer through a finned tube bundle in air cooled condenser-second assessment

Mathematical Modelling and Engineering Problems ◽

10.18280/mmep.050413 ◽

2018 ◽

Vol 5 (4) ◽

pp. 365-372 ◽

Cited By ~ 1

Author(s):

Yanán Camaraza-Medina ◽

Ángel M. Rubio-Gonzale ◽

Oscar M. Cruz-Fonticiella ◽

Osvaldo F. García-Morales ◽

Roberto Vizcón- Toledo ◽

...

Keyword(s):

Heat Transfer ◽

Tube Bundle ◽

Finned Tube ◽

Simplified Analysis

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Experimental investigation on the air-side flow and heat transfer characteristics of 3-D finned tube bundle

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2018.10.026 ◽

2019 ◽

Vol 131 ◽

pp. 506-516 ◽

Cited By ~ 9

Author(s):

Zi-yong Chen ◽

Min Cheng ◽

Qiang Liao ◽

Yu-dong Ding ◽

Jun-nan Zhang

Keyword(s):

Heat Transfer ◽

Experimental Investigation ◽

Tube Bundle ◽

Finned Tube ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Flow And Heat Transfer ◽

Side Flow

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Film Condensation of R-134a on Tube Arrays With Plain and Enhanced Surfaces: Part II—Empirical Prediction of Inundation Effects

Journal of Heat Transfer ◽

10.1115/1.2130401 ◽

2005 ◽

Vol 128 (1) ◽

pp. 33-43 ◽

Cited By ~ 16

Author(s):

D. Gstoehl ◽

J. R. Thome

Keyword(s):

Heat Transfer ◽

Local Heat ◽

Heat Transfer Process ◽

Finned Tube ◽

Film Condensation ◽

Condensation Temperature ◽

Asymptotic Model ◽

Transfer Coefficients ◽

Empirical Prediction ◽

R 134A

New predictive methods for R-134a condensing on vertical arrays of horizontal tubes are proposed based on visual observations revealing that condensate is slung off the array of tubes sideways and significantly affects condensate inundation and thus the heat transfer process. For two types of three-dimensional (3D) enhanced tubes, the Turbo-CSL and the Gewa-C, the local heat flux is correlated as a function of condensation temperature difference, the film Reynolds number, the tube spacing, and liquid slinging effect. The measured heat transfer data of the plain tube were well described by an existing asymptotic model based on heat transfer coefficients for the laminar wavy flow and turbulent flow regimes or, alternatively, by a new model proposed here based on liquid slinging. For the 26fpi low finned tube, the effect of inundation was found to be negligible and single-tube methods were found to be adequate.

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Analysis of Flow and Heat Transfer at a Finned Tube in Crossflow

Heat Transfer: Volume 3 ◽

10.1115/ht2003-47541 ◽

2003 ◽

Cited By ~ 1

Author(s):

Bharat K. Rangan ◽

Adarsh Krishnamurthy ◽

Vijay R. Raghavan

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Fundamental Problem ◽

Tube Bundle ◽

Cylindrical Tube ◽

Finned Tube ◽

Outer Diameter ◽

Duct Wall ◽

The Impact ◽

Fin Spacing

In the present study, a numerical investigation has been carried out into the fundamental problem of airflow past and heat transfer from a circular finned cylindrical tube, placed in a duct. The simulation is carried out using a finite volume method, based on laminar calculation of the transport quantities and employs an unsteady, 3-D, second order upwind scheme. As the work has importance in applications of air-cooled heat exchangers, practical values have been chosen for air velocity, air temperature, fin spacing and clearance between fin outer diameter and duct wall. In experimental determination of the performance of a finned-tube bundle, only overall average values such as drag coefficient and overall Nusselt number are possible. Local measurements are well nigh impossible, as any measurement instrument introduced into the narrow fin space will immediately change the flow field. This work gives an insight into variations of shear and heat transfer that will help the designer to optimize the fin spacing. The validity of the results for instantaneous velocity profiles and Nusselt number distribution comes from their physical plausibility. The agreement of the logical behavior of the studied variables when the fin space or fin clearance is modeled confirms the adequacy of the numerical simulation. The strong viscous effects caused by decreasing the fin space result in an increase in Cd and change in its frequency. Vortices generated on the rear section of the tube are damped, but the flow still shows small oscillations downstream of the tube, which indicates that vortex generation still exists, but has changed its location. Vortices augment the Nusselt number locally with increasing fin distance. Simultaneously, the opposite effect of converging boundary layers and therefore accelerated core flow in the fin space yields a maximum in the average Nusselt number as a function of fin space. The impact of decrease in the clearance between the tube and the duct wall is not as important as the effects of fin space.

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Problem issues of cores thermal-hydraulic calculation for prospective water-cooled reactors with supercritical parameters

Nuclear Power and the Environment ◽

10.31717/2311-8253.20.4.1 ◽

2020 ◽

Vol 19 (4) ◽

pp. 3-15

Author(s):

І. G. Sharaevsky ◽

◽

N. М. Fіаlkо ◽

А. V. Nоsоvskyi ◽

L. B. Zimin ◽

...

Keyword(s):

Heat Transfer ◽

Heat Exchange ◽

Exchange Process ◽

Physical Nature ◽

Heat Transfer Process ◽

Hydraulic Calculation ◽

Heated Wall ◽

Complex Nature ◽

Complex Flow ◽

Supercritical Parameters

The fundamental thermophysical features of the heat exchange process between the heated wall of a vertical channel and the light-water coolant of supercritical parameters concerning the conditions of heat-generating assemblies channels and cores of perspective energy nuclear reactors are considered. The available methods and recommendations for determining the limits of thermal load are analyzed. It is a guarantee the absence of the characteristic dangerous mode possibility of deteriorated heat exchange in these conditions and corresponding sharp rise in the channels wall temperature, which threatens their destruction. The physical nature of the occurrence of degraded heat transfer regimes remains unclear, and the existing approaches to the implementation of thermohydraulic calculation in such conditions are not sufficiently justified. The complex nature of intercellular heat and mass transfer in the fuel assembly and the presence of individual thermohydraulic cells with reduced levels of heat transfer intensity indicate that the existing method of determining the area of degraded heat transfer in the reactor core channels with supercritical parameters of the coolant is significantly simplified. Insufficient data and research results have been revealed to create adequate methods of heat-hydraulic calculation, suitable for taking into account the peculiarities of the heat transfer process complex flow under conditions of supercritical parameters of the coolant. The application of such methods should be the basis for ensuring the safe operation of prospective reactors and minimizing potential losses of a different nature from accidents caused by the destruction of cores through unacceptable heat transfer modes. To this end, the main direction of further research is identified.

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