PERFORMANCE ANALYSIS ON DOUBLE PIPE HEAT EXCHANGER … · a) Double pipe heat exchanger: A simplest form of heat exchanger is double pipe Heat Exchanger where two pipes are constructed

© June 2017 | IJIRT | Volume 4 Issue 1 | ISSN: 2349-6002

IJIRT 144608 INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 188

PERFORMANCE ANALYSIS ON DOUBLE PIPE

HEAT EXCHANGER USING WIRE COILED AND PIN

WIRE COILED TURBULATOR INSERTS

S.Shanmugapriya1, M.Ganesh karthikeyan2, Dr.M.Prabakar3 and S. Senthilkumar4 1Thermal Engineering, TRPEC, Trichy, India

2,3,4Mechanical Engineering, TRPEC, Trichy, India

Abstract—The heat exchanger is an important device in

almost all of the mechanical industries as in case of

process industries it is key element. Thus from long time

many researchers in this area are working to improve the

performance of these heat exchangers in terms of heat

transfer rate, keeping pressure drop in limit by using

various techniques. This project work deals with of such

techniques keeping focus on passive augmentation

techniques used in heat exchangers. Here the wire coiled

turbulator and pin wire coiled turbulator are used to

enhance the heat transfer rate in the double pipe heat

exchanger by changing the flow of a liquid. Tests to be

conducted at various mass flow rates by controlling the

flow control valve, for the following valve opens (25%,

50%, 75%, 100% valve open). Results may indicate that

the heat transfer rate enhances inversely with the pitch

of the wire coiled turbulator and directly proportional to

the mass flow rate.

Index Terms—Double pipe heat exchanger, Plain Tube,

Wire coiled turbulator inserts, Pin wire coiled turbulator

inserts, Pressure drop, Friction Co-efficient.

I. INTRODUCTION

Heat transfer can be increased by active and passive

techniques. In the active techniques external power is

required to increase the heat transfer. For the passive

technique method no external energy is required for

the enhancement of heat transfer. Wire coiled coil

matrix turbulator (WCCMT), taper wire coiled coil

matrix turbulator, and pin wire coiled turbulators are

falls under the category of passive techniques. In this

experimental work, turbulators are used to increase the

heat transfer. Three different types of wire coiled

turbulators (shown in figs.) are used to increase the

heat transfer. Due to the insertion of turbulators there

is increase in pumping power due to the pressure drop.

But when compared to enhancement in heat transfer

the increase in pumping power is very less.

II. TURBULATORS

Heat exchangers with the convective heat transfer of

fluid inside the tubes arefrequently used in many

engineering applications. In order to augment heat

transfer andincrease the system efficiency, turbulators

with different geometries have been developedand

many experimental investigations have been

conducted to determine theirthermodynamic

characteristics. The turbulators, when they are inserted

into the flow, provide redevelopment ofthe boundary

layer and increase the heat transfer surface area and

cause enhancement ofconvective heat transfer by

increasing turbulence. Thus, more compact and

economicheat exchanger with lower operation cost

can be produced. On the other hand, when

thesedevices placed into the flow they deteriorate the

flow.

Major Applications for Turbulators:

1. Oil Coolers

2. Highly viscous liquids

3. Gas or Air heaters/coolers

4. Static Mixers

5. Falling Film Evaporators

6. Inline reactors

7. Prevention of scale formation on tube.

a) Wire coiled and Pin Wire coiledturbulators:

The wire coiled turbulator is the old war horse of the

Turbulator world and ofcourse we make them in large

quantities. This type is also featured in the HTRI

softwareas a generic product so customers can do their

own design. (A type of wire Turbulator isalso featured

but as a proprietary product of Calgavin and

customized as per theirconfigurations.) We can give

all standard and a large range of custom pitches and

offerthem in almost all materials. While in most cases

the flexible wire type is a preferredoption, in the case



of retrofitting, where there is a lower flexibility with

regards toredesigning the existing equipment, this is

very often a low pressure drop reasonableefficiency

solution. So that I have selected wire coiled and pin

wire coiled turbulatorsformy research work.

b) Specifications of Wire Coiled Turbulator:

Fig. 1.Wire Coiled Turbulator

L = length of the wire coiled turbulator(1500 mm)

P = pitch (5mm, 10mm, 15mm)

D1 = Outer Diameter of the wire coil

turbulator(18mm)

D2 = inner Diameter of the wire coil turbulator.(6mm)

c) Wire Coiled Turbulator for Various Pitch:

Fig. 2 Wire coiled turbulator for 5mm pitch



d) Pin wire coiled turbulator:

Fig. 5 Pin wire coiled turbulator for 15mm pitch

III. EXPERIMENTAL SETUP AND

PROCEDURE

a) Double pipe heat exchanger:

A simplest form of heat exchanger is double pipe Heat

Exchanger where two pipes are constructed one inside

the other. One fluid flows in each of the pipes and gets

heated or cooled as per the application.

The major use of double pipe heat exchangers is

for sensible heating or cooling of process fluids

where small heat transfer areas (50 m2) are

required. This configuration is also suitable when

one or both fluids are at high pressure.

Double pipe heat exchangers Can operate

between 0.5KW~150KW.

Double pipe heat exchangers have an outer pipe

I.D of 50 to 400 mm at a nominallength of 1.5 to

12.0 m per hairpin. The O.D of the inner tube may

vary between 19 to 100 mm.

b) Reasons for selection:

The heat transfer coefficient and pressure drop are the

most significant variables in reducing the size and cost

of a heat exchanger. An increase in the heat transfer

coefficient generally leads to another advantage of

reducing the temperature driving force, which

increases the second law efficiency and decreases

entropy generation. Thus, research in this area

captivated the interest of a number of researchers. So,

the double pipe heat exchanger is selected.

The experimental setup is shown in fig. 6. It consists

of hot and water reservoir, Rota meter, thermocouples,

pumps, flow control valves and two concentric tubes

in which hot water flows through the inner tube

(Copper tube, d= 33 mm, L= 1550 mm) and cold water

flows in counter flow through annulus.The outer tube

is made of MS steel and it’s insulated with the asbestos



rope to minimize the heat loss with surroundings. Six

RTD Pt 100 type temperature sensors with ±0.1 °C

accuracy are used to measure the inlet and outlet

temperature of the hot and cold water.The water is

heated using 3 KW water heaters in the hot water tank

and the desired temperature controller. The water at

constant temperature is taken from the tank using the

centrifugal pump to the test section.

c) Experimental procedure:

The hot and cold water tank is filled with the

required level water.

The heater is switched on through the main power

supply of the setup.

The RTD (Relational Temperature Detector) is set

with the required temperature of hot water inlet.

Fig. 6Experimental setup

In this experiment there are two flow control

valves are used in that two initially one flow

control valve is closed and another one is open

this allow the fluid to fill in the container by using

this we measure the flow rate.

After that both the flow control valves are open

the cold water is entered into the inner pipe of the

setup.

The hot water is entered into an outer tube of the

heat exchanger through flow control valve.

The sensor measures the hot water and inlet and

outlet temperature and indicates in the

temperature indicator.

After taking the required readings the gate valves

is adjusted to the initial position.

Finally the heater and main power is switch OFF

and the water is drained.

d) Specifications:

(1) Inner Tube of the double pipe:

i.Material - Copper

ii.Inner diameter - 33 mm

iii.Outer diameter - 38 mm

iv.Length - 1550 mm

(2) Outer pipe of the double pipe:

i.Material - Mild steel

ii.Inner diameter - 63.5 mm

iii.Outerdiameter - 66.5 mm

iv.Length - 1450 mm

v.Insulation material - Asbestos

(3) Heater:

i.Capacity of heating coil – 1000W

ii.Number of heating coil - 3 no’s

(4) Pump:

i.Type - Centrifugal pump

ii.Power - ½ HP

iii.Number of pumps - 1no’s

iv. Cold water pump - 1no’s

e) Digital temperature indicator:

i. Sensor - RTD-Pt 100

ii. Number of sensors - 6 no’s

iii. Range - 0-199.9 °C

iv. Display unit - Digital LED)

v. Number of Channel - 10

f) Digital temperature controller:

i. Sensor - k-type

ii. Number of sensors - 6 no’s.

iii. Range - 0-400 °C



iv. Display unit -Digital (LED)

g) Hot and cold water tank:

i. Length - 0.47 m.

ii. Breadth - 0.47 m.

iii. Height - 0.75 m.20 liter container(used for

drinking water storage)

PVC pipe 0.5’’(length~1m)

Funnel (for feed input)

Rubber or plastic cap (to seal container)

Cap 0.5” (to seal effluent pipe)

Pipe (for gas output, was used LPG pipe) (1.5m)

Tyre tube (for store the biogas)

T- junction

M–seal

Black paint (to absorb heat energy from surroundings)

IV. DATA REDUCTION EQUATIONS

1. The average inside heat transfer coefficient and the

mean Nusselt number for the plain and the wire coiled

matrix turbulator cases are evaluated as:

Q = m Cp (T0 – Ti) = hi Ai (∆Ti) m

Where, Ai = π Di L

(∆Ti) m = (TMW-Ti) – (TMW-Ti)

ln (TMW-Ti)

(TMW-Ti)

TMW=TW/2

2. The average inside heat transfer co efficient

hi = (Q / Ai (∆Ti)m)

3. Nusseltnumber, friction factor, pressure drop

equations (plain tube):

Δp = 4fLVc2

2D2

4. Nusselt number, friction factor, pressure drop

equations (Plain tube with coiled turbulators):

Δp = 4fLVc2

2D2

V. RESULT AND DISCUSSION

The present experimental results on heat transfer and

friction characteristics in a plain tube are first

validated in terms of Nusselt number and friction

factor. It is important to compare the experimental

results obtained for the fully developed turbulent flow

for various turbulator inserts. At 25% valve open, with

a pitch of 5 mm, the wire coiled turbulators without

bonding have resulted in almost 2 times enhancement

when compared with plain tube. On the other hand, for

pitches of 10 mm and 15 mm the enhancement were

1.75 times and 1.5 times, respectively. At 50% valve

open, with a pitch of 5 mm, the wire coiled turbulators

without bonding have resulted in almost 1.83 times

enhancement when compared with plain tube. On the

other hand, for pitches of 10 mm and 15 mm the

enhancement were 1.66 times and 1.33 times,

respectively. At 75% valve open, with a pitch of 5 mm,

the wire coiled turbulators without bonding have

resulted in almost 1.75 times enhancement when

compared with plain tube. On the other hand, for

pitches of 10 mm and 15 mm the enhancement were

1.63 times and 1.37, respectively. At 100% valve

open, with a pitch of 5 mm, the wire coiled turbulators


enhancement when compared with plain tube. On the

other hand, for pitches of 10 mm and 15 mm the

enhancement were 1.45 times and 1.27 times,

respectively.

At 25% valve open, with a pin wire coiled turbulator


enhancement when compared with plain tube. At 50%

valve open, with a pin wire coiled turbulator without

bonding have resulted in almost 2.16 times

enhancement when compared with plain tube. At 75%

valve open, with a pin wire coiled turbulator without

bonding have resulted in almost 2 times enhancement

when compared with plain tube. At 100% valve open,



with a pin wire coiled turbulator without bonding have

resulted in almost 1.81 times enhancement when

compared with plain tube. On other hand the Nusselt

number, friction factor, and pressure drop are

indirectly proportional to the pitch.

Fig 7 Reynolds number Vs Experimental Heat

transfer co-efficient.

Fig 8 Reynolds number Vs Theoretical Heat

transfer co-efficient.

Figures 7 and 8 shows variation of Nusselt number

with Reynolds number for the different cases like plain

tube, wire coiled turbulator, taper wire coiled

turbulator, and pin wire coiled turbulator. It is

observed that the heat transfer rate is higher for pin

wire coiled turbulator while compare with other

turbulators.

Fig 9 Reynolds number Vs Experimental friction

factor.

Fig 10 Reynolds number Vs Theoretical friction

factor.

Figures 9 and 10 shows variation of friction factor with

Reynolds number for the different cases like plain

tube, wire coiled turbulator, taper wire coiled

turbulator,and pin wire coiled turbulator. It is observed

that the friction factor is higher for pin wire coiled

turbulator while compare with other turbulators.

0

5000

10000

15000

20000

25000

30000

0 100000

Exp

Hea

t tr

ansf

er c

o-e

ffic

ient

hex

p (

W/m

2K

)

Reynolds no

Reynolds no Vs Exp Heat

transfer co-efficient Plain

Tube

WCT

(5mm

Pitch)

WCT

(10mm

Pitch)

WCT

(15mm

Pitch)

0

1000

2000

3000

4000

5000

6000

0 100000Theo

reti

cal

Hea

t tr

ansf

er c

o-

effi

cien

t…

Reynolds no

Reynolds no Vs Theoretical

Heat transfer co-efficientPlain

Tube

WCT

(5mm

Pitch)

WCT

(10mm

Pitch)

WCT

(15mm

Pitch)

0

0.000001

0.000002

0.000003

0.000004

0.000005

0.000006

0 100000

fric

tion

fact

or

Reynolds no

Reynolds no Vs Exp friction

factorPlain Tube

WCT

(5mm

Pitch)WCT

(10mm

Pitch)WCT

(15mm

Pitch)Pin Wire

Coiled

Turbulator

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 100000

fric

tion

fact

or

Reynolds no


friction factorPlain Tube

WCT

(5mm

Pitch)

WCT

(10mm

Pitch)

WCT

(15mm

Pitch)

Pin Wire

Coiled

Turbulator



Fig 11.Reynolds number Vs Experimental

Pressure drop.

Figures 11 and 12 shows variation of pressure drop

with Reynolds number for the differentcaseslike plain

tube, it is observedthat the pressure dropis higher for

pin wire coiled turbulator while compare with other

turbulators.

Fig 12 Reynolds number Vs Theoretical Pressure

drop

VI. CONCLUSION

Experimental data obtained were compared with

those obtained from the theoretical data of plain tube.

The maximum Nusselt number for pitch 5 mm

was obtained which indicates that heat transfer

coefficient increases with the decreasing pitch of

the turbulator.

The friction factor also increases with the

decreasing pitch.

The above findings indicate that the use of wire

coiled coil matrix turbulator and pin wire coiled

turbulators in the tube-in-tube heat exchanger

enhances the heat transfer with considerable

pressure drop.

The experimental data which indicates the heat

transfer rate of pin wire coiled turbulator is

higher than the wire coiled turbulators.

REFERENCES

[ 1 ] P. Murugesan , K. Mayilsamy , S. Suresh ,

P.S.S. Srinivasan,Heattransfer and pressure

drop characteristics in a circular tube fitted

with and without V-cut twisted tape insert:

International Communications in Heat and

Mass Transfer 38(2011) 329–334.

[ 2 ] PaisarnNaphon, TanaponSuchana,Heat

transfer enhancement andpressure drop of the

horizontal concentric tube with twisted wires

brush inserts:International Communications in

Heat and Mass Transfer 38 (2011) 236–241.

[ 3 ] Halit Bas, VeyselOzceyhan,Heat transfer

enhancement in a tube withtwisted tape inserts

placed separately from the tube wall:

Experimental Thermaland Fluid Science 41

(2012) 51–58.

[ 4 ] PaisarnNaphon,Second law analysis on the

heat transfer of the horizontalconcentric tube

heat exchanger: Heat and Mass Transfer 33

(2006) 1029–1041.

[ 5 ] PaisarnNaphon,Effect of coil-wire insert on

heat transfer enhancement andpressure drop of

the horizontal concentric tubes: International

Communications inHeat and Mass Transfer 33

(2006) 753–763.

[ 6 ] Suresh S., M. Chandrasekar, S. Chandra

Sekhar,(2010) “ExperimentalStudies On Heat

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 100000

Exp

Pre

ssu

re D

rop

(∆P

) (

bar)

Reynolds no

Reynolds no Vs Exp Pressure

Drop Plain

Tube

WCT

(5mm

Pitch)

WCT

(10mm

Pitch)

WCT

(15mm

Pitch)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 100000

Th

eore

tica

l P

ress

ure

Dro

p

(∆P

) (

bar)

Reynolds no


Pressure DropPlain

Tube

WCT

(5mm

Pitch)

WCT

(10mm

Pitch)

WCT

(15mm

Pitch)



Transfer And Friction Factor Characteristics

Of Cuo/Water NanoFluid Under Turbulent

Flow In A Helically Dimpled Tube”,

ExperimentalThermal and Fluid Science, page

no. 542–549.

[ 7 ] Juin Chen a, Hans Muller-Steinhagen b,

Geoffrey G. Duffy a, (2001)“Heat Transfer

Enhancement in Dimpled Tubes”, Applied

Thermal Engineering,page no. 535-547.

[ 8 ] Pedro g, Vicente, Alberto Garcia, Antonio

Viedma, (2001) “Heat Transfer And Pressure

Drop For Low Reynolds Turbulent Flow In

Helically DimpledTubes’’,International

journal of Heat and Mass Transfer, page no.

543–553.

[ 9 ] Suresh S., K.P. Venkitaraj, P. Selvakumar,

(2010)“Comparative Study OnThermal

Performance Of Helical Screw Tape Inserts In

Laminar Flow UsingAl2o3/Water And

Cuo/Water Nanofluids”, Super lattice Microst,

page no 608–622.

[ 10 ] Juin Chen a, Hans Muller-Steinhagen b,

Geoffrey G. Duffy a, (2001)“Heat Transfer

Enhancement In Dimpled Tubes”, Applied

Thermal Engineering,page no. 535-547.

[ 11 ] Eiamsa-ard S. and Promvonge P. (2006)

“Experimental investigation ofheat transfer

and friction characteristics in a circular tube

fitted with V-nozzleturbulators”, International

Communications in Heat and Mass Transfer,

Vol.33,No.5, pp.591-600.

[ 12 ] Eiamsa-ard S. and Promvonge P. (2007) “Heat

transfer characteristics in atube fitted with

helical screw-tape with/without core-rod

inserts”, InternationalCommunications in Heat

and Mass Transfer, Vol.34, No.2, pp. 176-185.

Documents

PERFORMANCE ANALYSIS ON DOUBLE PIPE HEAT EXCHANGER … · a) Double pipe heat exchanger: A simplest form of heat exchanger is double pipe Heat Exchanger where two pipes are constructed