scholarly journals Use of kinetic flow energy liquids for vibration of local turbulizers in pipe heat exchangers

2020 ◽  
Vol 216 ◽  
pp. 01081
Author(s):  
Rakhimjan Babakhodjaev ◽  
Nazim Tashbaev ◽  
Djonreed Mirzaev
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Kinetic Energy ◽  
Heat Exchangers ◽  
Experimental Studies ◽  
The Other ◽  
Geometric Configuration ◽  
Flow Energy ◽  
Elastic Thread ◽  
Pipe Heat

This issue of using certain part of the kinetic energy of the flow for imparting vibration for special local turbulators (LT), consisting of an elastic thread with strung on it through a certain distance volume elements (made of a special material) of various geometric configuration installed in the tubes of the heat exchanger with fixing one end of the thread at the inlet, and the other end remains free. The results of numerical and experimental studies are presented, which show the effectiveness of the use of LT for intensifying the processes of hydrodynamics and heat transfer.

scholarly journals A CFD investigation and heat transfer augmentation of double pipe heat exchanger by employing helical baffles on shell and tube side

2021 ◽  
pp. 300-300
Author(s):  
Sobhanadri Anantha ◽  
Senthilkumar Gnanamani ◽  
Vivekanandan Mahendran ◽  
Venkatesh Rathinavelu ◽  
Ramkumar Rajagopal ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
The Other ◽  
Outlet Temperature ◽  
Shell Side ◽  
Shell And Tube ◽  
Double Pipe ◽  
Pipe Heat

The inclusion of baffles in a double pipe heat exchanger is becoming increasingly important as it improves the heat exchanger's performance. CFD analysis is used in this paper to investigate the performance of double pipe heat exchangers with and without helical baffles on both shell tube sides. The 3D Computation Fluid Dynamics (CFD) model was created in Solid Works, and the FloEFD software was used to analyze the conjugate Heat Transfer between the heat exchanger's tube and shell sides. Heat transfer characteristic like Outlet temperature of shell and tube are investigated along with pressure drop on shell and tube side. Based on CFD results of Double Pipe Heat exchanger with helical baffle on both shell side and tube side (Type 4) gives the better results than the other type of heat exchangers with an increased pressure drop than the others, results reveals that type 4 outlet temperature of shell side is 8% higher and on tube side it is 5.5% higher, also pressure drop on shell side is 12% higher and on tube side it is 42% higher than the other types.

scholarly journals Performance Enhancement of Double Pipe Heat Exchanger with Helical Fin and Vortex Generator using CFD

2019 ◽  
Vol 9 (2) ◽  
pp. 2677-2681
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Water Vapour ◽  
Food Processing ◽  
Heat Exchangers ◽  
Performance Enhancement ◽  
Delta Wing ◽  
Vortex Generator ◽  
Double Pipe ◽  
Pipe Heat

Transferring heat from one fluid to another fluid without losing of major energy is a challenging task in the food processing and other industries. Double Pipe Heat Exchanger (DPHE) are light capacity Heat Exchangers (HE) used for air and other gas applications. In the present work an attempt is made to enhance the heat transfer of DPHE with helical fins and vortex generator. The working fluids are air and steam (water vapour) along outer and inner pipes. The parameters considered are helix angles, i.e. 350 , 400 , & 450 and pitch size i.e. 80 mm, 75 mm and 70 mm, and a vertex generator. CATIA V5 and Autodesk CFD are used for modelling and analysis. It is found that 400 angle helix fin 70 mm pitch along Delta Wing type (Triangular) vortex generator (VG) gives best performance

Turbulent flows in a spiral double-pipe heat exchanger

2019 ◽  
Vol 30 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Zhe Tian ◽  
Ali Abdollahi ◽  
Mahmoud Shariati ◽  
Atefeh Amindoust ◽  
Hossein Arasteh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Turbulent Flows ◽  
Heat Exchangers ◽  
Volume Fraction ◽  
Inlet Temperature ◽  
Content Type ◽  
Tube Heat Exchanger ◽  
Double Pipe ◽  
Pipe Heat

Purpose This paper aims to study the fluid flow and heat transfer through a spiral double-pipe heat exchanger. Nowadays using spiral double-pipe heat exchangers has become popular in different industrial segments due to its complex and spiral structure, which causes an enhancement in heat transfer. Design/methodology/approach In these heat exchangers, by converting the fluid motion to the secondary motion, the heat transfer coefficient is greater than that of the straight double-pipe heat exchangers and cause increased heat transfer between fluids. Findings The present study, by using the Fluent software and nanofluid heat transfer simulation in a spiral double-tube heat exchanger, investigates the effects of operating parameters including fluid inlet velocity, volume fraction of nanoparticles, type of nanoparticles and fluid inlet temperature on heat transfer efficiency. Originality/value After presenting the results derived from the fluid numerical simulation and finding the optimal performance conditions using a genetic algorithm, it was found that water–Al2O3 and water–SiO2 nanofluids are the best choices for the Reynolds numbers ranging from 10,551 to 17,220 and 17,220 to 31,910, respectively.

scholarly journals DEVELOPMENT OF HIGH EFFICIENT SHELL-AND-TUBE HEAT EXCHANGERS BASED ON PROFILED TUBES

2020 ◽  
Author(s):  
Djamalutdin Chalaev ◽  
◽  
Nina Silnyagina ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Transfer Coefficient ◽  
Hydraulic Resistance ◽  
Heat Exchangers ◽  
Experimental Studies ◽  
Corrugated Tube ◽  
The Heat Transfer Coefficient

The use of advanced heat transfer surfaces (corrugated tubes of various modifications) is an effective way to intensify the heat transfer and improve the hydraulic characteristics of tubular heat exchangers. The methods for evaluating the use of such surfaces as working elements in tubular heat exchangers have not been developed so far. The thermal and hydrodynamic processes occurring in the tubes with the developed surfaces were studied to evaluate the efficiency of heat exchange therein. Thin-walled corrugated flexible stainless steel tubes of various modifications were used in experimental studies. The researches were carried out on a laboratory stand, which was designed as a heat exchanger type "tube in tube" with a corrugated inner tube. The stand was equipped with sensors to measure the thermal hydraulic flow conditions. The comparative analysis of operation modes of the heat exchanger with a corrugated inner tube of various modifications and the heat exchanger with a smooth inner tube was performed according to the obtained data. Materials and methods. A convective component of the heat transfer coefficient of corrugated tube increased significantly at identical flow conditions comparing with a smooth tube. Increasing the heat transfer coefficient was in the range of 2.0 to 2.6, and increased with increasing Reynolds number. The increase in heat transfer of specified range outstripped the gain of hydraulic resistance caused by increase of the flow. Results and discussion. CFD model in the software ANSYS CFX 14.5 was adapted to estimate the effect of the tube geometry on the intensity of the heat transfer process. A two-dimensional axially symmetric computer model was used for the calculation. The model is based on Reynolds equation (Navier-Stokes equations for turbulent flow), the continuity equation and the energy equation supplemented by the conditions of uniqueness. SST-turbulence model was used for the solution of the equations. The problem was solved in the conjugate formulation, which allowed assessing the efficiency of heat exchange, depending on various parameters (coolant temperature, coolant velocity, pressure). The criteria dependences were obtained Nu = f (Re, Pr). Conclusions. The use a corrugated tube as a working element in tubular heat exchangers can improve the heat transfer coefficient of 2.0 - 2.6 times, with an increase in hydraulic resistance in the heat exchanger of 2 times (compared with the use of smooth tubes). The criteria dependences obtained on the basis of experimental studies and mathematical modeling allow developing a methodology for engineering calculations for the design of new efficient heat exchangers with corrugated tubes.

Numerical Investigation on the Conjugate Heat Transfer in Double-Pipe Heat Exchangers With Propane Flow Boiling

Volume 3 ◽  
2004 ◽  
Author(s):  
Xuelei Chen ◽  
Mauricio A. Sa´nchez ◽  
William H. Sutton
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Computer Program ◽  
Heat Exchangers ◽  
Conjugate Heat Transfer ◽  
Flow Boiling ◽  
Experiment Data ◽  
Composite Fuel ◽  
Double Pipe ◽  
Pipe Heat

This investigation is part of the composite fuel project in the University of Oklahoma [1]. The composite fuel is a mixture resulted from natural gas resolving in liquid propane, which has a relatively lower storage pressure compared with that of compressed natural gas. Here in this paper, a numerical investigation of conjugate heat transfer among convection, wall conduction and flow boiling in a double-pipe heat exchanger is presented. The heat exchanger has hot fluid flowing in the annular section and propane boiling in the inside tube. A computer program is developed to calculate the conjugate heat transfer of convection, conduction and boiling. In computing the convection and conduction, control volume method and SIMPLE algorithm are used to solve momentum equations and the energy equation of conjugate heat transfer. The contribution of this work is to combine the third kind (Neuman) of boundary condition with the boiling correlations for flow boiling in horizontal tubes in order to calculate the conjugate heat transfer of the whole problem. Two boiling correlations have been selected to give inside tube boiling heat transfer coefficient. Because the boiling coefficient depends on the wall temperature and local propane quality, so we have to solve the boiling correlation, the conduction and the convection governing equations simultaneously. The iteration method and TDMA are used to solve these coupled equations. The two boiling correlations are Chen’s (1966) correlation [2] and Kandlikar’s (1990) correlation [3]. Finally the results are compared with the experiment data. It has been found in low quality range, Kandlikar’s result is close to the experiment data. Because very few data of propane flow boiling can be found in literature, we use propane pool boiling data by Shen, Spindler and Hahne (1997) [4] to estimate parameter Ffl in Kandlikar’s correlation. The influence of simultaneously developing velocity and temperature field at entrance length in annular passage is considered and discussed in detail. The wall conduction resistance is also compared with convection and boiling resistance in the whole length of the heat exchanger. The completed computer program can be used to the design of shell and tube heat exchangers.

Theoretical and experimental studies of heat transfer in a double-pipe heat exchanger equipped with twisted tape and nanofluid

2020 ◽  
Vol 135 (2) ◽  
Author(s):  
Reza Aghayari ◽  
Heydar Maddah ◽  
Seyed Mohsen Pourkiaei ◽  
Mohammad Hossein Ahmadi ◽  
Lingen Chen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Experimental Studies ◽  
Twisted Tape ◽  
Double Pipe ◽  
Pipe Heat

scholarly journals Implementation of GRNN for Evaluating the Pressure Drop and Heat Transfer in a Heat Exchanger by Utilizing Triple Elliptical Leaf Angle Strips with Same Orientation and Opposite Direction

2019 ◽  
Vol 8 (6) ◽  
pp. 4333-4340
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Opposite Direction ◽  
Heat Exchangers ◽  
Industrial Applications ◽  
Design Parameters ◽  
Leaf Angle ◽  
Statistical Tool ◽  
Experimental Values ◽  
Pipe Heat

Heat exchangers are the basic devices which are used in many areas wherever applications of heat flow occurs. Its usage varies from common domestic devices to mighty industrial applications. The performance of the heat exchanger shows a very important role for its utilization in many aspects. This performance is not dependent on the design parameters in a particular relationship hence experimental values for thermal performance are taken by utilizing three elliptical leaf strips in a tube and pipe heat exchanger. The three elliptical leaves used in experiment has major to minor axes ratios as 2:1 and distance of 50 mm between two leaves are arranged at different angular orientations from 00 to 1800 with 100 intervals. The leaves are placed in the tube side with same orientation and opposite direction of flow and experimentation is conducted to obtain the values. Based on these datasets available a statistical tool is utilized known as GRNN for the comparison between these obtained experimental values & GRNN values. From this comparison the percentage of error between the values is identified as result.

A Semi Empirical Methodology for Performance Estimation of a Double Pipe Finned Heat Exchanger

2008 ◽  
Author(s):  
G. Arvind Rao ◽  
Yeshyahou Levy
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Wide Range ◽  
Double Pipe ◽  
Semi Empirical ◽  
Pipe Heat

Finned tubes are one of the most widely used means of passively enhancing the heat transfer in circular tubes. Many investigators have proposed different correlations for predicting the performance of such heat exchangers based on their experimental investigations. However, the practical usage of such correlations is limited because of the variety of parameters that can influence Nusselt number and friction factor. Most of the correlations either have been developed with limited databases, or are geometry specific. Using CFD for analyzing performance of such heat exchangers is very computational intensive and hence cannot practically be applied for design optimization purposes. On the other hand, empirical correlations have many limitations in terms of their applicability. The objective of the present article is to present a physically based model for evaluating heat transfer and frictional loss for an internally and / or externally finned double pipe heat exchanger that can be applied in a wide range of operating conditions of practical importance. This paper describes a simple semi-empirical-numerical methodology to evaluate heat transfer and pressure drop characteristics in a finned tube heat exchanger with internal and/or external fins. Conduction and turbulent forced convection are the prominent modes of heat transfer. In order to resolve the operational characteristics of double pipe finned heat exchangers, a numerical methodology is presented which uses well known existing correlations for flow in a smooth pipe and flow over a flat plate. The method of successive substitution is used to solve the problem numerically. The proposed methodology is applied to some simple cases and the results compare well with existing data and correlations available in the literature. It is found that the addition of fins to such double pipe heat exchangers reduce the Nusselt Number; however the corresponding heat transfer rate is enhanced owing to the increase in the overall heat transfer area.

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