EFFECT OF BAFFLE ORIENTATION ON HEAT TRANSFER AND PRESSURE DROP OF SHELL AND TUBE HEAT EXCHANGERS WITH AND WITHOUT LEAKAGE FLOWS

2008 ◽  
Author(s):  
Koorosh Mohammadi ◽  
Wolfgang Heidemann ◽  
Hans Mueller-Steinhagen
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Leakage Flows ◽  
Shell And Tube

Enhancement of Convective Heat Transfer in Internal Viscous Flows by Inserting Motionless Mixers

2009 ◽  
Author(s):  
Ramin K. Rahmani ◽  
Anahita Ayasoufi ◽  
Theo G. Keith
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Turbulent Flows ◽  
Heat Exchangers ◽  
Convection Heat Transfer ◽  
Viscous Fluids ◽  
High Rate ◽  
Working Fluid ◽  
Static Mixer ◽  
Shell And Tube

In chemical processing industries, heating, cooling and other thermal processing of viscous fluids are an integral part of the unit operations. Enhancement of the natural and forced convection heat transfer rates has been the subject of numerous academic and industrial studies. Motionless mixers, also known as static mixers, are often used in continuous mixing, heat transfer, and chemical reactions applications. These mixers have low maintenance and operating costs, low space requirements, and have no moving parts. Heat exchangers equipped with mixing elements are especially well suited for heating or cooling highly viscous fluids. Shell and tube heat exchangers incorporate static mixing elements in the tubes to produce a heat transfer rate significantly higher than that of conventional heat exchangers. The mixing elements continuously create a new interface between the working fluid and tube wall, thereby producing a uniform heat history in the fluid. It is desired to employ motionless mixers in heat transfer applications to provide a high rate of heat transfer from a thermally homogenous fluid with low pressure drop. In the past, laboratory experimentation has been a fundamental part of the design process of a new static mixer for a given application as well as the selection of an existing static mixer. It is possible to use powerful computational fluid dynamics (CFD) tools to study the performance of these mixers without resorting to experimentation. In this paper, which is an extension to the previous work of the authors, the enhancement of performance of shell and tube heat exchangers by inserting motionless mixers (SMX and helical) is studied for creeping, laminar, and low-Re turbulent flows. It is shown that the studied mixers produced similar flow histories for the working fluid considered. Both SMX and helical mixers are able to increase thermal performance of heat exchangers. The SMX mixer manifests a higher performance in temperature blending and in heat transfer enhancement compared to the helical mixer. However, the pressure drop created by SMX elements, and consequently the required energy to maintain the flow in tube, is significantly higher.

Experimental Study and Genetic-Algorithm-Based Correlation on Shell-Side Heat Transfer and Flow Performance of Three Different Types of Shell-and-Tube Heat Exchangers

2006 ◽  
Vol 129 (9) ◽  
pp. 1277-1285 ◽  
Author(s):  
Qiu-wang Wang ◽  
Gong-nan Xie ◽  
Bo-tao Peng ◽  
Min Zeng
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Transfer Coefficients ◽  
Shell Side ◽  
Heat Transfer Coefficients ◽  
Friction Factors ◽  
Shell And Tube

The heat transfer and pressure drop of three types of shell-and-tube heat exchangers, one with conventional segmental baffles and the other two with continuous helical baffles, were experimentally measured with water flowing in the tube side and oil flowing in the shell side. The genetic algorithm has been used to determine the coefficients of correlations. It is shown that under the identical mass flow, a heat exchanger with continuous helical baffles offers higher heat transfer coefficients and pressure drop than that of a heat exchanger with segmental baffles, while the shell structure of the side-in-side-out model offers better performance than that of the middle-in-middle-out model. The predicted heat transfer rates and friction factors by means of the genetic algorithm provide a closer fit to experimental data than those determined by regression analysis. The predicted corrections of heat transfer and flow performance in the shell sides may be used in engineering applications and comprehensive study. It is recommended that the genetic algorithm can be used to handle more complicated problems and to obtain the optimal correlations.

On the Presentation of Performance Data for Enhanced Tubes Used in Shell-and-Tube Heat Exchangers

1983 ◽  
Vol 105 (2) ◽  
pp. 358-365 ◽  
Author(s):  
W. J. Marner ◽  
A. E. Bergles ◽  
J. M. Chenoweth
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Initial Step ◽  
Performance Data ◽  
Flow And Heat Transfer ◽  
Enhanced Tubes ◽  
Shell And Tube ◽  
Efficient Heat Transfer ◽  
The Many

As the efforts to produce more efficient heat transfer equipment continue, an increasing number of augmented surfaces are being produced commercially. Consequently, the designer faces an almost overwhelming task in comparing and evaluating the performance of various surfaces because of the many different ways in which the test data are currently presented in the literature. Thus, a uniform format for presenting pressure drop and heat transfer data for enhanced surfaces has become a necessity. This paper is concerned with one important aspect of this problem, namely, that of tubular enhanced surfaces used in shell-and-tube heat exchangers. As an initial step, the subject is limited to single-phase pressure drop and heat transfer; however, both tubeside and shellside flow are taken into consideration. A comprehensive list of commerical augmented tubes which may be considered for use in shell-and-tube exchangers is given, along with a survey of the performance data which are available in the literature. A standardized data format which uses the inside and outside envelope diameters as the basis for presenting the various geometrical, flow, and heat transfer parameters for all tubular enhanced surfaces is proposed and discussed.

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 Computational Fluid Dynamics Analysis of Flow Patterns, Pressure Drop, and Heat Transfer Coefficient in Staggered and Inline Shell-Tube Heat Exchangers

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shubham Sharma ◽  
Shalab Sharma ◽  
Mandeep Singh ◽  
Parampreet Singh ◽  
Rasmeet Singh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Heat Transfer Analysis ◽  
Staggered Grid ◽  
Shell Side ◽  
Shell And Tube

In this numerical study, the heat transfer performance of shell-and-tube heat exchangers (STHXs) has been compared for two different tube arrangements. STHX having 21 and 24 tubes arranged in the inline and staggered grid has been considered for heat transfer analysis. Shell-and-tube heat exchanger with staggered grid arrangement has been observed to provide lesser thermal stratification as compared to the inline arrangement. Further, the study of variation in the mass flow rate of shell-side fluid having constant tube-side flow rate has been conducted for staggered grid structure STHX. The mass flow rate for the shell side has been varied from 0.1 kg/s to 0.5 kg/s, respectively, keeping the tube-side mass flow rate as constant at 0.25 kg/s. The influence of bulk mass-influx transfer rate on heat transfer efficiency, effectiveness, and pressure drop of shell-tube heat exchangers has been analyzed. CFD results were compared with analytical solutions, and it shows a good agreement between them. It has been observed that pressure drop is minimum for the flow rate of 0.1 kg/s, and outlet temperatures at the shell side and tube side have been predicted to be 40.94°C and 63.63°C, respectively.

Application of Nanofluids in a Shell-and-Tube Heat Exchanger

2013 ◽  
Author(s):  
Jonathan Cox ◽  
Anoop Kanjirakat ◽  
Reza Sadr
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Nano Particles ◽  
Experimental Result ◽  
Tube Heat Exchanger ◽  
Shell And Tube

Innovations in the field of nanotechnology have potential to improve industrial productivity and performance. One promising applications of this emerging technology is using nanofluids with enhanced thermal properties. Nanofluids, engineered colloidal suspensions consisting of nano-sized particles (less than 100nm) dispersed in a basefluid, have shown potential as industrial cooling fluids due to the enhanced heat transfer characteristics. Experiments are conducted to compare the overall heat transfer coefficient and pressure drop of water vs. nanofluids in a laboratory scale industrial type shell and tube heat exchanger. Three mass particle concentrations, 2%, 4% and 6%, of SiO2-water nanofluids are formulated by dispersing 20 nm diameter nano particles in desalinated water. Nanofluid and tap water are then circulated in the cold and hot loops, respectively, of the heat exchanger to avoid direct particle deposition on heater surfaces. Interestingly, experimental result show both augmentation and deterioration of heat transfer coefficient for nanofluids depending on the flow rate through the heat exchangers. This trend is consistent with an earlier reported observation for heat transfer in micro channels. This trend may be explained by the counter effect of the changes in thermo-physical properties of fluids together with the fouling on the heat exchanger surfaces. The measured pressure drop in the nanofluids flow shows an increase when compared to that of basefluid that could limit the use of nanofluids in heat exchangers for industrial application.

An Experimental Study of Shell-and-Tube Heat Exchangers With Continuous Helical Baffles

2007 ◽  
Vol 129 (10) ◽  
pp. 1425-1431 ◽  
Author(s):  
B. Peng ◽  
Q. W. Wang ◽  
C. Zhang ◽  
G. N. Xie ◽  
L. Q. Luo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Tube Bundle ◽  
Shell Side ◽  
Helical Baffle ◽  
Shell And Tube

Two shell-and-tube heat exchangers (STHXs) using continuous helical baffles instead of segmental baffles used in conventional STHXs were proposed, designed, and tested in this study. The two proposed STHXs have the same tube bundle but different shell configurations. The flow pattern in the shell side of the heat exchanger with continuous helical baffles was forced to be rotational and helical due to the geometry of the continuous helical baffles, which results in a significant increase in heat transfer coefficient per unit pressure drop in the heat exchanger. Properly designed continuous helical baffles can reduce fouling in the shell side and prevent the flow-induced vibration as well. The performance of the proposed STHXs was studied experimentally in this work. The heat transfer coefficient and pressure drop in the new STHXs were compared with those in the STHX with segmental baffles. The results indicate that the use of continuous helical baffles results in nearly 10% increase in heat transfer coefficient compared with that of conventional segmental baffles for the same shell-side pressure drop. Based on the experimental data, the nondimensional correlations for heat transfer coefficient and pressure drop were developed for the proposed continuous helical baffle heat exchangers with different shell configurations, which might be useful for industrial applications and further study of continuous helical baffle heat exchangers. This paper also presents a simple and feasible method to fabricate continuous helical baffles used for STHXs.

The Sensitivity of Heat Exchanger Calculations to Uncertainties in the Physical Properties of the Process Fluids

1983 ◽  
Vol 197 (3) ◽  
pp. 171-178 ◽  
Author(s):  
L E Haseler ◽  
R G Owen ◽  
R G Sardesai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Physical Properties ◽  
Heat Exchangers ◽  
Simple Procedure ◽  
Heat Transfer Area ◽  
Heat Exchanger Design ◽  
Shell And Tube ◽  
Design Calculations

The various processes occurring in shell and tube heat exchangers are examined for their dependence on the physical properties of the fluid streams. This dependence, coupled with estimates of likely uncertainties in the various properties, is used in developing a simple procedure for evaluating the resultant uncertainty in heat exchanger design calculations. Two case studies, which use a well-tested computer program, have shown that the above procedure adequately quantifies the uncertainties in the calculation of heat transfer area and pressure drop.

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