The document discusses a tube-in-tube helical heat exchanger analysis using ANSYS CFD. It varies the curvature ratio from 8 to 25 and inlet velocity from 1 to 2 m/s to analyze parameters like Nusselt number, friction factor, and pressure drop. Graphs of these parameters versus Reynolds number are created and discussed to determine optimal heat exchanger performance. The analysis aims to improve heat transfer characteristics of coiled heat exchangers, which provide enhanced and compact heat transfer due to secondary flow effects from pipe curvature.
The aim of this experiment is to measurement linear thermal along z direction conductivity and to investigate and verify Fourier’s Law for linear heat conduction along z direction and we proved that K is inversely proportional with ΔT, and we have many errors in our experiment that made the result not clear.
This presentation is on shell and tube heat exchanger in which its design parameters and its troubleshooting conditions designed for better understanding and learning of all
Selection of Heat Exchanger Types
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND
5 FACTORS INFLUENCING SELECTION
5.1 Type of Duty
5.2 Temperatures and Pressures
5.3 Materials of Construction 5.4 Fouling
5.5 Safety and Reliability
5.6 Repairs
5.7 Design Methods
5.8 Dimensions and Weight
5.9 Cost
5.10 GBHE Experience
6 TYPES OF EXCHANGER
6.1 Shell and Tube Exchangers
6.2 Cylindrical Graphite Block Heat Exchangers
6.3 Cubic Graphite Block Heat Exchangers
6.4 Air Cooled Heat Exchangers
6.5 Gasketed Plate and Frame
6.6 Spiral Plate
6.7 Tube in Duct
6.8 Plate-fin
6.9 Printed Circuit Heat Exchanger (PCHE)
6.10 Scraped Surface/Wiped Film Exchangers
6.11 Welded or Brazed Plate
6.12 Double Pipe
6.13 Electric Heaters
6.14 Fired Process Heaters
TABLE
(1) ADVANTAGES AND DISADVANTAGES OF DIFFERENT SHELL AND TUBE DESIGNS
FIGURES
1 ESTIMATED MAIN PLANT ITEM COSTS
2 ESTIMATED INSTALLED COSTS
3 TEMA HEAT EXCHANGER NOMENCLATURE
4 F ‘CORRECTION FACTORS' : TEMA E SHELL WITH EVEN NUMBER OF PASSE
5 SHELL AND TUBE HEAT EXCHANGER HEAD TYPES
6 GENERAL ARRANGEMENT OF A CYLINDRICAL GRAPHITE BLOCK HEAT EXCHANGER
7 EXPLODED VIEW OF A CUBIC GRAPHITE BLOCK
HEAT EXCHANGER
8 TYPICAL AIR COOLED HEAT EXCHANGER
9 GENERAL VIEW OF ONE END OF A 3-STREAM
PLATE-FIN HEAT EXCHANGER
10 TYPICAL PCHE PLATE
11 VICARB ‘COMPABLOC' EXCHANGER
12 ‘BROWN FINTUBE' MULTITUBE HEAT EXCHANGER
13 FIRED HEATER : SCHEMATICS AND NOMENCLATURE
The aim of this experiment is to measurement linear thermal along z direction conductivity and to investigate and verify Fourier’s Law for linear heat conduction along z direction and we proved that K is inversely proportional with ΔT, and we have many errors in our experiment that made the result not clear.
This presentation is on shell and tube heat exchanger in which its design parameters and its troubleshooting conditions designed for better understanding and learning of all
Selection of Heat Exchanger Types
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND
5 FACTORS INFLUENCING SELECTION
5.1 Type of Duty
5.2 Temperatures and Pressures
5.3 Materials of Construction 5.4 Fouling
5.5 Safety and Reliability
5.6 Repairs
5.7 Design Methods
5.8 Dimensions and Weight
5.9 Cost
5.10 GBHE Experience
6 TYPES OF EXCHANGER
6.1 Shell and Tube Exchangers
6.2 Cylindrical Graphite Block Heat Exchangers
6.3 Cubic Graphite Block Heat Exchangers
6.4 Air Cooled Heat Exchangers
6.5 Gasketed Plate and Frame
6.6 Spiral Plate
6.7 Tube in Duct
6.8 Plate-fin
6.9 Printed Circuit Heat Exchanger (PCHE)
6.10 Scraped Surface/Wiped Film Exchangers
6.11 Welded or Brazed Plate
6.12 Double Pipe
6.13 Electric Heaters
6.14 Fired Process Heaters
TABLE
(1) ADVANTAGES AND DISADVANTAGES OF DIFFERENT SHELL AND TUBE DESIGNS
FIGURES
1 ESTIMATED MAIN PLANT ITEM COSTS
2 ESTIMATED INSTALLED COSTS
3 TEMA HEAT EXCHANGER NOMENCLATURE
4 F ‘CORRECTION FACTORS' : TEMA E SHELL WITH EVEN NUMBER OF PASSE
5 SHELL AND TUBE HEAT EXCHANGER HEAD TYPES
6 GENERAL ARRANGEMENT OF A CYLINDRICAL GRAPHITE BLOCK HEAT EXCHANGER
7 EXPLODED VIEW OF A CUBIC GRAPHITE BLOCK
HEAT EXCHANGER
8 TYPICAL AIR COOLED HEAT EXCHANGER
9 GENERAL VIEW OF ONE END OF A 3-STREAM
PLATE-FIN HEAT EXCHANGER
10 TYPICAL PCHE PLATE
11 VICARB ‘COMPABLOC' EXCHANGER
12 ‘BROWN FINTUBE' MULTITUBE HEAT EXCHANGER
13 FIRED HEATER : SCHEMATICS AND NOMENCLATURE
ONGC Training on Heat Exchangers, Compressors & PumpsAkansha Jha
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Analysis of Heat Transfer in Spiral Plate Heat Exchanger Using Experimental a...ijsrd.com
Heat transfer is the key to several processes in industrial application. In a present days maximum efficient heat transfer equipment are in demand due to increasing energy cost. For achieving maximum heat transfer, the engineers are continuously upgrading their knowledge and skills by their past experience. Present work is a skip in the direction of demonstrating the use of the computational technique as a tool to substitute experimental techniques. For this purpose an experimental set up has been designed and developed. Analysis of heat transfer in spiral plate heat exchanger is performed and same Analysis of heat transfer in spiral plate heat exchanger can be done by commercially procurable computational fluid dynamic (CFD) using ANSYS CFX and validated based on this forecasting. Analysis has been carried out in parallel and counter flow with inward and outward direction for achieving maximum possible heat transfer. In this problem of heat transfer involved the condition where Reynolds number again and again varies as the fluid traverses inside the section of flow from inlet to exit, mass flow rate of working fluid is been modified with time. By more and more analysis and experimentation and systematic data degradation leads to the conclusion that the maximum heat transfer rates is obtained in case of the inward parallel flow configuration compared to all other counterparts, which observed to vary with small difference in each section. Furthermore, for the increase heat transfer rate in spiral plate heat exchanger is obtain by cascading system.
Enhancement of heat transfer in tube in-tube heat exchangers using twisted in...Ijrdt Journal
Heat exchangers have several industrial and engineering applications. There are different methods to enhance heat transfer in heat exchangers. Passive technique of heat transfer is the most economical and best suited one. The role of inserts in internal forced convection has been widely acknowledged as a passive device in the heat transfer enhancement. One of such technique is introduction of twisted inserts which enhances the heat transfer coefficient. Twisted aluminium inserts when placed in the path of the fluid flow, creates a high degree of turbulence resulting in an increase in the heat transfer rate. By placing inserts, it is expected that the benefits due to the increased heat transfer coefficient overcome the higher cost involved because of the increased frictional losses. The work mainly focuses on increasing the heat transfer of tube-in-tube heat exchangers by using twisted aluminium inserts. The results obtained from the tube with twisted aluminium insert are compared with those without twisted insert using standard properties of heat transfer (LMTD & Effectiveness). The relations based on the data gathered during this work for predicting the heat transfer coefficient of the horizontal pipe with twisted taped insert are proposed. According to the results, in order to obtain maximum heat transfer, the twist ratio must be at the lowest level.
Ijri te-03-011 performance testing of vortex tubes with variable parametersIjripublishers Ijri
Conventional refrigeration system is a type of refrigeration systems which are costly; noisy, harmful gases released from a machine based on application of this type of system and it is required more maintenance. So, we need to go for unconventional refrigeration systems like vortex tube refrigeration system, which produce less vibrations and which require less maintenance and which are noiseless. It is required for our mechanical engineers to look for enhancing the performance of such vortex tubes. So as a part of my project work, I have chosen various sizes of vortex tubes and test their performances for finding out optimum performance. We will be testing the performance of vortex tubes with different ‘l/d’ ratios and different cold fractions, with different pressures and different nozzle sizes.
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Heat exchangers are the important engineering systems with wide variety of applications including power plants, nuclear reactors, refrigeration and air-conditioning systems, heat recovery systems, chemical processing and food industries. Helical coil configuration is very effective for heat exchangers and chemical reactors because they can accommodate a large heat transfer area in a small space, with high heat transfer coefficients. This project focus on an increase in the effectiveness of a heat exchanger and analysis of various parameters that affect the effectiveness of a heat exchanger and also deals with the performance analysis of heat exchanger by varying various parameters like number of coils, flow rate and temperature. The results of the helical tube heat exchanger are compared with the straight tube heat exchanger in both parallel and counter flow by varying parameters like temperature, flow rate of cold water and number of turns of helical coil.
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Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
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When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
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About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
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Heat exchanger, types and workind Report
1. 1
Contents
ACKNOWLEDGEMENT ......................................................................................................................................................2
ABSTRACT ..............................................................................................................................................................................2
INTRODUCTION....................................................................................................................................................................3
Heat exchanger......................................................................................................................................................................3
Classification of heat exchangers ......................................................................................................................................3
Tabular heat exchanger........................................................................................................................................................3
Double pipe heat exchanger................................................................................................................................................4
Advantages ............................................................................................................................................................................5
Methodology adopted..........................................................................................................................................................5
Analysis procedure...............................................................................................................................................................5
Geometrical modelling ........................................................................................................................................................5
Sketching................................................................................................................................................................................6
Sweep .....................................................................................................................................................................................6
Merging..................................................................................................................................................................................6
Meshing..................................................................................................................................................................................6
Boundary conditions............................................................................................................................................................6
Solution methods..................................................................................................................................................................6
RESULTS AND DISCUSSIONS ..........................................................................................................................................7
Results and discussions .......................................................................................................................................................7
Graphs ....................................................................................................................................................................................7
Nu Vs Re................................................................................................................................................................................7
friction factor Vs Re.............................................................................................................................................................8
pressure drop Vs Re .............................................................................................................................................................8
pressure drop.........................................................................................................................................................................8
Conclusion and future scope...................................................................................................................................................9
Future scope..........................................................................................................................................................................9
2. 2
ACKNOWLEDGEMENT
I would like to express my deep sense of gratitude and respect to my supervisor for his
excellent guidance, suggestions and constructive criticism. Working under his supervision
greatly contributed in improving quality of my research work and in developing my
engineering and management skills.
I am extremely fortunate to be involved in such an exciting and challenging research project.
It gave me an opportunity to work in a new environment of Fluent. This project has increased
my thinking and understanding capability.
I would like to thank all whose direct and indirect support helped me in completing my thesis
in time.
ABSTRACT
There is a wide application of coiled heat exchanger in the field of cryogenics and other
industrial applications for its enhanced heat transfer characteristics and compact structure. Lots
of researches are going on to improve the heat transfer rate of the helical coil heat exchanger.
Here, in this work, an analysis has been done for a tube-in-tube helical heat exchanger with
constant heat transfer coefficient with turbulent flow. There are various factors present that
may affect the heat transfer characteristics of the heat exchanger. Here, the experiment has
been done by varying the curvature ratio i.e. ratio of coil diameter to inner tube diameter and
inlet velocity of the hot fluid in the inner tube. The curvature ratio is varied from 8 to 25 and
inlet velocity is varied from 1m/s to 2m/s step wise. The analysis has done using ANSYS 13
CFD methodology. Different parameters are calculated from the results obtained and graphs
are plotted between various parameters such as Nusselt number, friction factor, pressure drop
and pumping power versus Reynolds number. These graphs have been analyzed and discussed
to find out the optimal result for which the heat exchanger would give the best performance
3. 3
INTRODUCTION
Heat exchanger:
A heat exchanger may be defined as an equipment which transfers the energy from a hot
fluid to a cold fluid, with maximum rate and minimum investment and running cost. The
rate of transfer of heat depends on the conductivity of the dividing wall and convective
heat transfer coefficient between the wall and fluids. The heat transfer rate also varies
depending on the boundary conditions such as adiabatic or insulated wall conditions.
Some examples of heat exchangers are:
i. Intercoolers and pre heaters.
ii. Condensers and boilers in refrigeration units.
iii. Condensers and boilers in steam plant.
iv. Regenerators.
v. Oil coolers and heat engines.
Automobile radiators etc
Classificationofheat exchangers
Tabular heat exchanger:
These kinds of heat exchangers are mainly made up of circular coils whereas many different
shapes are also used for different applications. They provide flexibility because the geometric
parameters such as length, diameter can be modified easily. These are used for phase change
such as condensation, evaporation kind of operations. Again it is classified in to three
different categories i.e. double pipe heat exchanger, spiral tube heat exchanger and shell and
tube heat exchanger
4. 4
Double pipe heat exchanger:
These are the simplest heat exchangers used in industries. These heat exchangers are cheap
for both design and maintenance, making them a good choice for small industries. In this
kind of heat exchanger, two tubes or pipes having different diameters are placed
concentrically, the smaller one inside the larger one. The two fluids, in between which heat
transfer is required, flows in the two different tubes. The curvature of the tube gives rise to a
secondary flow which makes the flow turbulent and increases the heat transfer rate.
Figure 1 Model of tube-in-tube helical heat exchanger
The utilization, conversion, and recovery of energy in commercial, industrial, and domestic
applications usually involve a heat transfer process such as refrigerator, air conditioner etc.
Improved quality of heat exchanger above the usual practice can significantly improve the
thermal efficiency as well as the economics of their design and production. It has been
observed that heat transfer rate in helical coils heat exchanger are higher than that of a
straight tube. They are also compact in size. For this helical coil heat exchangers are being
widely used in many industrial applications such as nuclear industries, power generation,
process plants, refrigeration, heat recovery systems, food industries, etc.The reason behind
higher heat transfer rate of helical heat exchanger is that, due to the swirl flow in a coiled tube,
centrifugal forces arises which gives rise to secondary flow pattern. It consists of two vertices
perpendicular to the axial flow direction. As a result, the heat transfer takes place by diffusion
in the radial direction and by convection. The contribution of the convective heat transfer
5. 5
dominates the overall process and significantly enhances the heat transfer rate per unit length
of the tube, as compared to the heat transfer rate of a straight tube of equal length.
Advantages
1. It has larger surface area and compact volume as compared to straight tube heat
exchanger.
2. It eliminates the dead-zones that are common drawbacks in the shell and tube type
heat exchangers because the whole surface area of the curved pipe is exposed to the
moving fluid.
3. They give improved heat transfer characteristics because of small wall resistance.
4. Because of coil like structure it can withstand thermal shock and eliminates thermal
expansion.
5. METHODOLOGY
Methodologyadopted:
Here the analysis is done using ANSYS 14 software.
Analysis procedure:
Geometrical modelling
Meshing
Solution:
Material selection
Defining zones
Boundary conditions
Solution methods
Solution initialization
Iteration
Geometrical modelling:
First the geometry of the model is created in ANSYS workbench. Fluid flow (fluent) module
is selected from the workbench. The design modeler opens as a new window when the
geometry is double clicked.
6. 6
Sketching :
Using sketching option three concentric circles are created in XY-plane(diameters of circles
are 6mm, 7mm and 13mm) in three different sketches. A straight line is also created in
sketch 4 along the height of the helical tube at the centre.
Sweep:
Then the three circles were swept about the central axis with pitch 40 mm and number of
turns is 1.5. At first the mean coil diameter is 50mm and then it is varied for different values
of D/d. Then using boolean operation the overlapping volumes are subtracted and respective
phases were chosen.
Merging:
The model has 3 parts and 3bodies after sweep operation. So, all the 3 parts are selected
using control and merged into 1 part. At the end it will have 1 part and 3 bodies. The 3
bodies are named as follows:
1. Inner fluid (fluid)
2. Thickness volume (solid)
3. Outer fluid (fluid)
Meshing:
In free meshing a relatively coarser mesh is generated. It contains both tetrahedral and
hexahedral cells having triangular and quadrilateral faces at the boundaries. Later, a fine
mesh is generated using edge sizing. In this, the edges and regions of high pressure and
temperature gradients are finely meshed
Boundary conditions:
Different boundary conditions were applied for different zones. Since it is a tube-in-tube heat
exchanger, there are two inlets and two outlets. The inlets were defined as velocity inlets and
outlets were defined as pressure outlets. The inlet velocity of the cold fluid was kept constant
i.e. 2.5m/s, whereas velocity of hot fluid was varied from 1m/s to 2m/s for different
experiments. The outlet pressures were kept default i.e. atmospheric pressure. The hot fluid
temperature at inlet was 650C and cold fluid inlet temperature was kept 230C. The other wall
conditions were defined accordingly.
Solution methods:
The solution methods were set as follows:
1. Scheme = Simplc
7. 7
2. Gradient = Least Square Cell Based
3. Pressure = linear
4. Momentum = Second Order Upwind
5. Turbulent Kinetic Energy = Second Order Upwind
6. Turbulent Dissipation Rate = Second Order Upwind
7. Energy= power law
RESULTS AND DISCUSSIONS
Results and discussions:
The heat transfer and flow characteristics of a helical coil pipe can be observed from the
contour diagrams of temperature and pressure distribution, variation of Nusselt number,
friction factor and pumping power with Reynolds number.
Graphs:
Using the values obtained from CFD analysis as given in the above tables, graphs are plotted
between various parameters from which the fluid flow characteristics and heat transfer can
be easily visualized.
Nu Vs Re
250
200
150
100
Nu Vs Re
50
0
0 5000 10000 15000 20000 25000 30000
Figure 4 Graph between Nusselt number Vs Reynold number for D/d=8
8. 8
frictionfactor Vs Re
0.066
0.065
0.064
0.063
0.062
0.061
0.06 friction factor Vs Re
0.059
0.058
0.057
0.056
0 5000 10000 15000 20000 25000 30000
Figure 5 Graph between Reynold number Vs friction factor for D/d
pressure drop Vs Re
pressure
drop
8000
7000
6000
5000 D/d=8
4000 D/d=10
3000 D/d=15
2000 D/d=20
1000 D/d=25
0
0 5000 10000 15000 20000 25000 30000
Figure 6 Gaph between pressure drop & Re for different D/d
Above figure 4, 5, ) it is observed that the Nusselt number, increases with increasing
Reynolds number whereas friction factor decreases with increasing Re. For the optimal
condition of heat exchanger, pumping power should be minimum with maximum
Nusselt number, i.e. the power consumption should be l.In the figures 6, it can be seen
that with increasing pressure dro
9. 9
Conclusionand future scope:
This work investigates the heat transfer and flow characteristics of a tube-in-tube helical heat
exchanger for counter flow using CFD methodology. The effect of mass flow rate in the inner
tube and curvature ratio are studied and the various conclusions drawn are:
i.
Nusselt depends on the curvature ratio, i.e. the ratio of coil diameter to
inner tube diameter. Nu increases with increasing curvature ratio. Also
it was found that Nu
ii. Increases with increasing mass flow rate or Reynolds number.
iii.
For turbulent flow in the pipe, friction factor decreases with increasing
Reynolds number(Re) whereas heat transfer rate increases with Re. So,
there exists an optimal
iv. Value of mass flow rate and curvature ratio for which the heat
exchanger would give the best performance.
For more heat transfer rate, higher curvature ratio should be preferred irrespective of the
power low.
From the velocity and temperature contours it can be observed that the velocity is higher
towards the outer side of the coil whereas temperature is higher towards
inner side of coil.
The heat transfer performance of a helical tube heat exchanger is more than that of a straight
tube heat exchanger
Future scope:
Future works required to be carried out for further improvement of helical heat exchangers.
CFD analysis and optimization of the curvature ratio using Dean number and
Colburn factor for boundary conditions of constant wall temperature and constant
wall heat
Flux for both laminar and turbulent flow.
To analyze the results and optimize the heat transfer rate with varying the pitch of
the helical coil.