b

UNIVERSITI TEKNOLOGI MARAFAKULTI KEJURUTERAAN KIMIAPROCESS ENGINEERING LABORATORY II(CPE554)

Name: NURUL AIN BINTI ZULKIFLEEstudent id: 2013452866Group : 4Experiment: Shell and tube heat exchangerdate performed: 11TH march 2015SEMESTER: 4programme / code: eh2214a / CPE554submit to : ms habsah alwi

No.TitleAllocated Marks (%)Marks

1Abstract/Summary5

2Introduction5

3Aims5

4Theory5

5Apparatus5

6Methodology/Procedure10

7Results10

8Calculations10

9Discussion 20

10Conclusion10

11Recommendations5

12Reference5

13Appendix5

TOTAL MARKS100

Remarks:

70

Checked by:

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Date:

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ABSTRACTThe objective of this experiment is to evaluate and study the function as well as the performance of shell and tube heat exchanger at various operating conditions. The conditions are:1) Heat Load and Heat Balance, LMTD, Overall Heat Transfer Coefficient (U)2) Turbulent/Laminar Flow, Reynolds Number Shell Side, Reynolds Number Tube Side3) Heat Transfer Coefficients 4) Pressure Drop, Shell Side, Tube Side

[EDIT]From the data collected, the configuration of Shell and Tube heat exchanger in counter current flow has a higher effectiveness than the co-current flow.

INTRODUCTIONA heat exchanger is equipment built for efficientheat transferthat takes place between two fluids that enter and exit at different temperatures. The media may be separated by a solid wall to prevent mixing or they may be in direct contact. The main function of heat exchanger is to either remove heat from a hot fluid or to add heat to the cold fluid. They are widely used in space heating, refrigeration, air-conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air.

The direction of fluid motion inside the heat exchanger can normally categorised as parallel flow, counter flow and cross flow. In this experiment, only parallel flow and counter flow is highlighted. For parallel flow, also known as co-current flow, both the hot and cold fluids flow in the same direction. Both the fluids enter and exit the heat exchanger on the same ends. For counter flow, both the hot and cold fluids flow in the opposite direction. Both the fluids enter and exit the heat exchanger on the opposite ends. In this experiment, shell and tube heat exchanger is focused on.

AIMSTo evaluate and study the performance of the Shell and Tube Heat Exchanger at various operating conditions. The conditions are 1) Heat Load and Heat Balance, LMTD, Overall Heat Transfer Coefficient (U)2) Turbulent/Laminar Flow, Reynolds Number Shell Side, Reynolds Number Tube Side3) Heat Transfer Coefficients 4) Pressure Drop, Shell Side, Tube Side

THEORYHeat exchangers are devices designed to transfer heat from one fluid to another without the fluids coming into contact. Shell-and-tube heat exchanger is the most common type of heat exchanger in industrial applications. They contain a large number of tubes packed in a shell with their axes parallel to that of the shell. Heat transfer takes place as one fluid flows inside the tubes while the other fluid flows outside the tubes through the shell.

Figure 1: a) Co-current Flow and b) Counter Current Flow

a) Co-current (Parallel) flowThe flow of the hot and the cold fluid is taking place in the same direction in this case. As the graph shown in Figure 1a, the temperature difference between the hot and the cold fluid keeps on decreasing from one end to the other.

b) Counter current flowThe hot fluid enters from one end of the exchanger and the cold from the opposite end. This results in nearly constant temperature difference between the hot and the cold fluid. This is a significant aspect and makes counter current exchangers preferable over co-current exchangers.

Shell and Tube Heat Exchangers Construction

Figure 2: Construction of Shell and Tube Heat Exchanger

a) TubesThe tubes provide the heat transfer area in a shell and tube heat exchanger. The tubes in a shell and tube heat exchanger are arranged in various arrangements. They are enclosed by a shell around them. They are available in various sizes and shapes according to B.W.G (Birmingham wire gauge) system. The selection of wall thickness of tube depends on maximum operating pressure and corrosion characteristics.

b) Tube PitchVarious aspects have to be kept in mind while designing a shell and heat tube exchanger. The tubes cannot be made very close to each other as that would then leave very less amount of metal between the drilled tubes holes in tube sheets attached at the ends of the exchanger. And if the space between the tubes is very high, it would result in less surface area which in turn, would affect the efficiency of the exchanger. Hence, an optimum distance should be maintained. The shortest distance between centers of two adjacent tubes is called the tube pitch, should not be less than 1.25 times the tube diameter.

c) Shell As shown in the Figure 2, the shell is the outer casing of the heat exchanger. One fluid flows between the outer wall of the heat exchanger and inner wall of the shell while the other flows inside the tube. Shell has a circular cross section and selection of material of the shell depends upon the corrosiveness of the fluid and the working temperature and pressure. Carbon steel is a common material for the shell under moderate working conditions.

d) BafflesThese are panels responsible for obstructing and redirecting the flow of fluid in the shell side of an exchanger. They are situated normal to the walls of the shell and force the liquid to flow at right angles to the axis of the tubes. This increases turbulence resulting in greater heat transfer. Also, the baffles help in keeping the tubes from sagging and increase the strength of the tubes by preventing their vibration.

Heat BalanceFor a parallel-flow shell and tube heat exchanger with one tube pass and one shell pass shown in Figure 1a, the heat balance is given as: Similarly, for the counterflow shell and tube heat exchanger with one tube pass and one shell pass, the heat balance is given as: where,= mass flowrate of cold fluid in the tube= mass flowrate of hot fluid in the shell= specific heat of cold fluid in the tube= specific heat of hot fluid in the shell= temperature of cold fluid entering/leaving the tube= temperature of hot fluid entering/leaving the shell= heat exchange rate between fluid

Heat TransferThe general equation for heat transfer across the tube surface in a shell and tube heat exchanger is given by:

where,= outside area of the tube= inside area of the tube= mean temperature difference= overall heat transfer coefficient based on the outside area of the tube= overall heat transfer coefficient based on the inside area of the tube

The coefficients and are given by:

and

where,= outside fluid film coefficient= inside fluid film coefficient = outside dirt coefficient (fouling factor)= inside dirt coefficient= thermal conductivity of the tube wall material= tube outside diameter= tube inside diameter

The mean temperature difference for both parallel and counterflow shell and tube heat exchanger with single shell pass and single tube pass is normally expressed in terms of log-mean temperature difference (LMTD)

Figure 3: Temperature profile for a 1:2 heat exchanger

For a more complex heat exchanger, such as 1:2 heat exchanger in Figure 3, an estimate of the true temperature difference is given by:

where is the temperature correction factor as a function of two dimensionless temperature ratios R and S:

Having calculated R and S, then is determined from the standard correction factor figures in Figure 6.

Tube-side Heat-transfer Coefficient, For turbulent flow, Sieder-Tate equation can be used:

where,= Reynolds Number = = = Nusselt Number = = Prandtl Number = = equivalent (or hydraulic) diameter (m)= 4 (cross-sectional area of flow)/wetted perimeter= mass velocity, mass flow per unit area= fluid viscosity of bulk fluid temperature = fluid viscosity at the wall= fluid density = fluid velocity in tube = fluid specific heat, heat capacity= 0.023 for non-viscous liquids= 0.027 for viscous liquids=Fluid thermal conductivity

For laminar flow (Re < 2000), the following correlation is used:

where,L = the tube length (m)

Tube-side Pressure Drop, The tube-side pressure drop is given by:

where,= tube-side pressure drop= number of tube-side passes= tube dimensionless friction factor in Figure 8= length of one tube, (m)= tube-side velocity= 0.25 for laminar, Re < 2100= 0.14 for turbulent, Re > 2100

Shell-side Heat-transfer Coefficient, (Kerns Method)In order to determine the heat transfer coefficient for fluid film in shell, first calculate the cross-sectional area of flow for hypothetical row of tubes of the shell as follows:

where,= tube outside diameter (m)= tube pitch (m)= shell inside diameter (m)= distance between baffle (m)

Then, the shell-side mass velocity, and linear velocity, are calculated as follows:

where,= Fluid flowrate on the shell-side = shell-side fluid density

The shell equivalent diameter, is given by:= = (For square pitch arrangement)

= = (For equilateral triangular pitch arrangement)

Thus, Reynolds number in shell is given by:= =

Baffle cut, , is used to specify the dimensions of a segmental baffle. It is the height of the segment removed to form the baffle, expressed as a percentage of the baffle disc diameter.

Using this Reynolds number and given value, the heat transfer factor, value is determined from Figure 9. Then, the heat transfer coefficient for fluid film in shell is calculated from:

Shell-side Pressure Drop, (Kerns Method)The shell-side pressure drop is given by:

where,= shell pressure drop= shell dimensionless friction factor in Figure 10= distance between baffle (m)= shell-side velocity

Shell-side Heat-transfer Coefficient, (Bells Method)The shell-side heat transfer coefficient is given by:

where,= heat transfer coefficient calculated for cross-flow over an ideal tube bank, no leakage or by-passing= correction factor to allow for the effect of the number of vertical tube rows= window effect correction factor= by-pass stream correction factor= leakage correction factor

The ideal cross-flow heat transfer coefficient is given by:

where,= =

Heat-transfer coefficient for an ideal cross-flow tube banks can be calculated using the heat transfer factors, from Figure 11.

The correction factor is determined as follows:a. For Re > 2000, turbulent, take from Figure 12b. For Re > 100 to 2000, transition region, take c. For Re < 100, laminar region,

where, numbers of rows crossed in series from end to end of the shell.

The window correction factor is plotted against , in Figure 13 where is the ratio of the numbers of tubes in the window zones to the total number in the bundle.

The by-pass correction factor is for /2

where,= 1.5 for laminar flow, Re < 100= 1.35 for transitional and turbulent flow Re > 100= clearance area between the bundle and the shell= maximum area for cross-flow= number of sealing strips encountered by the by-pass streamin the cross-flow zone= the number of constrictions, tube rows, encountered in thecross-flow section

If there is no sealing strips used, is obtained from Figure 14.The leakage correction factor is,

where,= a factor obtained from Figure 15= tube-to-baffle clearance area, per baffle= shell-to-baffle clearance area, per baffle= total leakage area,

Shell-side Pressure Drop, (Bells Method)The total shell-side pressure drop is the sum of pressure drop in cross-flow and window zones, determined separately. The pressure drop in the cross-flow zones between the baffle tips is calculated from the correlations for ideal tube banks, and corrected for leakage and bypassing.

where,= pressure drop calculated for an equivalent ideal tube bank= number of tube rows crossed (in the cross-flow region)= shell-side velocity, based on the clearance area at the bundle equator= friction factor from Figure 16 for Re calculated with us= by-pass correction factor= leakage correction factor

Calculate with for laminar region, Re < 100 and for transition and turbulent region, Re > 100. If no sealing strips used, take from Figure 17

Calculate from Equation 22 taking from Figure 18

The window-zone pressure drop is,

where,= geometric mean velocity = = velocity in the window zone = = shell-side fluid mass flow= number of restrictions for cross-flow in window zone, approximately equal to the number of tube rows

The end-zone pressure drop is,

Thus, the total shell-side pressure drop is the sum of pressure drops over all the zones in series from inlet to outlet:= 2(end zones) + ()(crossflow zones) + (window zones)=

where,

Shell and Bundle GeometryThe shell and bundle geometry described below shall be used for calculating the correction factors above.

Where,= baffle cut height= , where is the baffle cut as a fraction= height from the baffle chord to the top of the tube bundle= bundle cut = = angle subtended by the baffle chord (rads)= bundle diameter

Subsequently,= = =

where,= vertical tube pitch= for square pitch= 0.87 for equilateral triangular pitch

The number of tubes in a window zone is given by:

where can be obtained from Figure 20, for the appropriate bundle cut, .

The number of tubes in a cross-flow zone Nc is given by:

and

where is obtained from Figure 20 for the appropriate baffle cut, .

where is the diametrical tube-to-baffle clearance, typically 0.8 mm.

where is the baffle-to-shell clearance and can be obtained from Figure 20 for the appropriate baffle cut, Bc.

where is the baffle spacing.

APPARATUS1) Shell and Tube Heat Exchanger2) Stopwatch

Figure 4: Heat Exchanger Training Apparatus (Model: HE158C)

Figure 5: Schematic Diagram for Heat Exchanger Training Apparatus

PROCEDUREGeneral Start-up 1) A quick inspection is performed to make sure that the equipment is in a proper working condition.2) All valves are ensured to be initially closed, except V1 and V12.3) Hot water tank is filled up via a water supply hose connected to valve V27. The valve is closed once the tank is full.4) The cold-water tank is filled up by opening valve V28 and the opened valve is left for continues water supply.5) A drain hose is connected to the cold water drain point.6) The main power is switched on. The heater is switched on for the hot water tank and the temperature controller is set to 50C.7) The water temperature is allowed in the hot water tank to reach the set-point.8) The equipment is now ready to be run.

General Shut-down 1) Heater is switched off. Wait until the hot water temperature drops below 40C.2) Pump P1 and pump P2 are switched off.3) Main power switched off.4) All water in the process lines is drained off. Water in the hot and cold water tanks are retained for next laboratory session.5) All valves are closed.

Experiment A: Counter-Current Shell & Tube Heat Exchanger1) General start-up procedures is performed.2) The valves are switched to counter-current Shell & Tube Heat Exchanger arrangement.3) Pumps P1 and P2 are switched on.4) Valves V3 and V14 are opened and adjusted to obtain the desired flowrates for hot water and cold water streams, respectively.5) The system is allowed to reach steady state for 10 minutes.6) FT1, FT2, TT1, TT2, TT3 and TT4 is recorded.7) The pressure drop measurements are recorded for shell-side and tube-side for pressure drop studies.8) Steps 4 to 7 is repeated for different combinations of flowrate FT1 and FT2 as in the results sheet.9) Pumps P1 and P2 are switched off after the completion of experiment.10) The next experiment is proceeded.

Experiment B: Co-Current Shell & Tube Heat Exchanger1) The valves are switched to co-current Shell & Tube Heat Exchanger arrangement2) Pumps P1 and P2 are switched on.3) The valves are switched to counter-current and the air is bled with high water flowrate if there is air trap in the shell-side. Then the valves are switched position back to co-current position.4) Valves V3 and V14 are opened and adjusted to obtain the desired flowrates for hot water and cold water streams, respectively.5) The system is allowed to reach steady state for 10 minutes.6) FT1, FT2, TT1, TT2, TT3 and TT4 is recorded.7) The pressure drop measurements are recorded for shell-side and tube-side for pressure drop studies.8) Steps 5 to 8 are repeated for different combinations of flowrate FT1 and FT2 as in the results sheet.9) Pumps P1 and P2 are switched off after the completion of experiment.10) Shut-down the equipment is proceeded.

RESULTSExperiment A: Counter-Current Shell & Tube Heat ExchangerFI 1 (LPM)FI 2 (LPM)TT1 (C)TT2 (C)TT3 (C)TT4 (C)DPT1 (mmH2O)DPT1 (mmH2O)

21030.829.238.149.3193-5

41031.529.243.148.8195-5

61032.229.344.049.2191-5

81033.329.744.849.5192-5

101034.029.845.148.7191-5

FI 1 (LPM)FI 2 (LPM)TT1 (C)TT2 (C)TT3 (C)TT4 (C)DPT1 (mmH2O)DPT1 (mmH2O)

10241.429.947.549.16.0-5

10437.930.246.649.169.0-5

10635.429.245.649.0126-5

10834.028.944.948.9214-5

101033.228.944.648.9377-5

HOT FLUID (TUBE)TEST12345

VOLUMETRIC FLOWRATE (LPM)1010101010

MASS FLOW RATE(kg/s)0.16470.16470.16470.16470.1647

HEAT TRANSFER RATE(J/s)3162.991925.01100.17825.13618.85

COLD FLUID (SHELL)TEST12345

VOLUMETRIC FLOWRATE(LPM)2.004.006.008.0010.00

MASS FLOWRATE(kg/s)0.033190.06640.09960.13280.1659


TEST12345

T LOG MEAN, )17.9419.5819.5019.8519.15

HEAT LOSS(W)3051.931702.87683.68325.34235252

EFFICIENCY(%)3.5111.5437.8660.57134.60

OVERALL HEAT TRANSFER COEFFICIENTTEST12345

Total exchange area(0.050.050.050.050.05

Overall heat transfer coefficient

3526.191966.291128.38831.36646.32

TUBE SIDETEST12345

CROSS SECTION AREA(0.0005570.0005570.0005570.0005570.000557

MASS VELOCITY

295.69295.69295.69295.69295.69

LINEAR VELOCITY(m/s)0.29920.29920.29920.29920.2992

REYNOLDS NUMBER14337.7914337.7914337.7914337.7914337.79

PRANDTL NUMBER3.563.563.563.563.56

NUSELT NUMBER73.9473.9473.9473.9473.94

TYPE OF FLOWturbulentturbulentturbulentturbulentturbulent

STANTON NUMBER0.001450.001450.001450.001450.00145

HEAT TRANSFER FACTOR, 0.003390.003390.003390.003390.00339

TUBE COEFFICIENT,

1786.331786.331786.331786.331786.33

SHELL SIDETEST12345

CROSS FLOW AREA(0.00480.00480.00480.00480.0048

MASS VELOCITY

6.9213.8320.7527.6734.56


EQUIVALENT DIAMETER(m)0.05160.05160.05160.05160.0516

REYNOLDS NUMBER445.76891.261337.201783.152227.17

PRANDTL NUMBER5.445.445.445.445.44

NUSELT NUMBER5.299.2112.7516.0519.17

TYPE OF FLOWlaminarlaminarlaminarlaminarLaminar

STANTON NUMBER0.002180.001900.0017520.001650.00158


SHELL COEFFICIENT,

63.14427.62609.79855.541068.58

Experiment B: Co-Current Shell & Tube Heat ExchangerFI 1 (LPM)FI 2 (LPM)TT1 (C)TT2 (C)TT3 (C)TT4 (C)DPT1 (mmH2O)DPT1 (mmH2O)

21029.931.438.649.5679604

41029.931.843.248.8678601

61030.032.744.349.2675583

81030.133.745.450.0678530

101030.234.045.449.4676527

FI 1 (LPM)FI 2 (LPM)TT1 (C)TT2 (C)TT3 (C)TT4 (C)DPT1 (mmH2O)DPT1 (mmH2O)

10230.338.147.248.723526

10430.436.046.648.97524

10630.334.446.048.9653524

10830.134.045.648.7670523

101030.033.745.249.0712530

HOT FLUID (TUBE)TEST12345

VOLUMETRIC FLOWRATE (LPM)1010101010

MASS FLOW RATE(kg/s)0.16470.16470.16470.16470.1647


COLD FLUID (SHELL)TEST12345

VOLUMETRIC FLOWRATE(LPM)2.004.006.008.0010.00

MASS FLOWRATE(kg/s)0.033190.06640.09960.13280.1659


TEST12345

T LOG MEAN, )17.9419.5819.5019.8519.15

HEAT LOSS(W)3051.931702.87683.68325.34235252

EFFICIENCY(%)3.5111.5437.8660.57134.60

OVERALL HEAT TRANSFER COEFFICIENTTEST12345

Total exchange area(0.050.050.050.050.05

Overall heat transfer coefficient

3526.191966.291128.38831.36646.32

TUBE SIDETEST12345

CROSS SECTION AREA(0.0005570.0005570.0005570.0005570.000557

MASS VELOCITY

295.69295.69295.69295.69295.69


REYNOLDS NUMBER14337.7914337.7914337.7914337.7914337.79

PRANDTL NUMBER3.563.563.563.563.56

NUSELT NUMBER73.9473.9473.9473.9473.94

TYPE OF FLOWturbulentturbulentturbulentturbulentturbulent

STANTON NUMBER0.001450.001450.001450.001450.00145


TUBE COEFFICIENT,

1786.331786.331786.331786.331786.33

SHELL SIDETEST12345

CROSS FLOW AREA(0.00480.00480.00480.00480.0048

MASS VELOCITY

6.9213.8320.7527.6734.56


EQUIVALENT DIAMETER(m)0.05160.05160.05160.05160.0516

REYNOLDS NUMBER445.76891.261337.201783.152227.17

PRANDTL NUMBER5.445.445.445.445.44

NUSELT NUMBER5.299.2112.7516.0519.17

TYPE OF FLOWlaminarlaminarlaminarlaminarLaminar

STANTON NUMBER0.002180.001900.0017520.001650.00158


SHELL COEFFICIENT,

63.14427.62609.79855.541068.58

Temperature Profile for counter-current Shell and Tube Heat ExchangerHeat transfer Coefficient Study

CALCULATIONSThe specific results for this experiment allow us to determine the heat transfers, heat losses, heat transfer coefficient and LMTD values.Tube O.D. : 9.53 mmTube I.D. : 7.75 mmTube Length : 500 mmTube Count : 10 (single pass)Tube Pitch : 18 mmTube arrangement: TriangleShell O.D.: 100 mmShell I.D. : 85 mmBaffle Count: 8Baffle Cut : 20 %Baffle Distance : 50 mmMaterial of Construction: 316 L Stainless Steel/Borosilicate Glass

Hot waterCold water

Density: 988.18 kg/m3Density: 995.67 kg/m3

Heat capacity: 4175.00 J/kg.KHeat capacity: 4183.00 J/kg.K

Thermal cond: 0.6436 W/m.KThermal cond: 0.6155 W/m.K

Viscosity: 0.0005494 Pa.sViscosity:0.0008007 Pa.s

Experiment A: Counter-Current Shell & Tube Heat Exchanger

[Fixed Cold Water Flow Rate 10 LPM]1) Calculations of heat transfer and heat lostThe heat transfers of both hot and cold water are both calculated using the heat balance equation.

Heat transfer rate for hot water i) = 220.03 W

ii) 632.60 W

iii) = 1196.44 W

iv) = 1980.31 W

v) = 2887.96 W

Heat transfer rate for cold water i) = 7774.46 W

ii) = 3956.64 W

iii) = 3609.57 W

iv) = 3262.50 W

v) = 2498.93 W

Heat Lost Rate = i) ii) iii) iv) v)

Efficiency = i) ii) iii) iv) v)

2) Calculations of Log Mean Temperature Differencei) = = =

ii) = =

iii) = =

iv) = =

v) = =

3) Calculation of the tube and shell heat transfer coefficients by Kerns methodFor 1-shell pass; 1-tube pass,

Heat transfer coefficient at Tube side:Cross Flow Area, A= = =

Total cross Flow Area, = 0.0000472 number of tubes= 0.0000472 10= 0.000472 m2

Mass velocity, = = =

Linear Velocity, = = =

Reynolds No, Re= = = (Turbulent Flow)

Prandtl No, Pr= = = 5.44

Tube Side Coefficient, hi= = =

Heat transfer coefficient at Shell side:Cross Flow Area, A= = =



Equivalent Diameter, = = =

Reynolds No, Re= = = (Laminar Flow)

Prandtl No, Pr= = = 5.44Shell Side Coefficient, hi= = =

Overall heat transfer coefficientCross Flow Area, A= = =

Overall heat transfer coefficient, U= = = -111.80 4) Calculation of Pressure Drop across Tube and Shell= = = 338.8 Pa

= = = 3.3 Pa

[Fixed Hot Water Flow Rate 10 LPM]1) Calculations of heat transfer and heat lostThe heat transfers of both hot and cold water are both calculated using the heat balance equation.


ii) = 5294.59 W

iii) = 4263.17 W

iv) = 3506.80 W

v) = 2956.72 W


ii) = 694.15 W

iii) = 1416.06 W

iv) = 2221.27 W

v) = 2984.84 W




ii) = =

iii) = =

iv) = =

v) = = undefined

















= = = 3.3 Pa

DISCUSSIONIn this experiment, there are a few objectives that are need to be achieved which are, to demonstrate the working principles of concentric flow heat exchanger under counter-current and co-current flow conditions, to observe the effect of the heat water inlet temperature variation on the performance characteristic of a concentric tube heat exchanger, to show the effect of flow rate variation on the performance of a concentric heat exchanger and the major part of the objectives is to determine the most efficient flow of concentric tube heat exchanger whether it is the counter-flow or co-current flow.

In addition, double pipe concentric heat exchanger is used to archive these objectives. It is combined with thermometers and the flow rates meter. Moreover, the control of the hot fluids temperature and both hot and cold fluid flow rates were made much easier.

Furthermore, notice that for both experiment 3a and 3b, the counter-flow produce greater efficiency that co-current flow. This result obey the theoretical conclusion where the counter-flow heat exchanger is more efficient that co-current flow.

Moreover, there are a lot of mistakes and error that might have affected the results obtained. The most common error occurred during the experiment is parallax error. The eye position is not perpendicular to the scale when recording the temperatures of the fluids. Besides that, the flow rates always change easily during the experiments and the reading of in from the typical laboratory thermometer is merely different from the reading on the digital thermometer.

Based on the calculation that had been done, it was found out that the values of LMTD for co-current flow is higher than the counter-current flow. But, the overall heat transfer coefficient for counter-current flow is higher than the co-current flow. This mean that counter current flow heat exchanger has a higher effectiveness.

CONCLUSIONThis experiment shows that the shell and tube heat exchanger follows the basic law of thermodynamics. In parallel (co-current) flow configuration, the exit temperature of the hot fluid is always higher than the exit temperature of the cold fluid. In counter-current flow configuration, the exit temperature of the hot fluid is also higher than the exit temperature of the cold fluid. However, in counter current flow configuration, the exit temperature of the cold fluid is higher than the exit temperature of the cold fluid in co-current configuration. Hence, it is clear that for heat exchanger, counter current flow configuration has a higher effectiveness than the co-current flow configuration. The experiment shows that when the flow rate of one of the stream increases, the rate of heat transfer will also increases. The amount of heat loss form the hot water is not equal to the heat gain by the cold water due to the heat loss to the surrounding. From the calculations done, the LMTD (log mean temperature difference) for co-current flow is higher than the counter-current flow. However, the overall heat transfer coefficient for counter-current flow is higher than the co-current flow. As a conclusion, counter current flow configuration of heat exchanger is more preferred for practical application. One of the applications of heat exchanger is oil cooler.

RECOMMENDATIONSThere are few recommendations that are needed to be considered when conducting this experiment so that the result obtained can be more accurate and precise. First, the eye position should be perpendicular to the meniscus and the scale. This can prevent parallax error from occurring. Next, the experiment should be repeated at least 3 times in order to get an accurate data which will be more convincing.Furthermore, the flow rates and the temperature must be monitored regularly during the experiment to ensure that they remain constant. This can reduced the possibility for error to occur and achieved the main objective of the experiment. In addition, the equipment must be check first in order to avoid any error such as leakage. Always check and rectify any leak and make sure that the heater is fully immersed in the water. It must assure to run properly. Other than that, be extremely careful when handling liquid at high temperature. Do not touch the hot components of the unit as it may cause a serious injury.The amount of cold water must be continuous in order to avoid the reducing of hot water because if the hot water reduced into critical level it might cause an explosion. Lastly, always switch off the heater and allow the liquid to cool down before draining it out.

REFERENCES1. Chopey, N.P. Handbook of Chemical Engineering Calculations (2nd Edition), McGraw-Hill, 1994.2. Coulson, J.M. and Richardson, J.F. Chemical Engineering, Volume 1 (3rd Edition), Pergamon Press, 1977.3. Coulson, J.M. and Richardson, J.F. Chemical Engineering, Volume 6 (Revised 3rd Edition), Butterworth-Heinemann, 1996.4. Kern, D.Q. Process Heat Transfer (Intl Edition), McGraw-Hill, 1965.5. Perry, R.H., Green, D.W. and Maloney, J.O. Perrys Chemical Engineering Handbook (6th Edition), McGraw-Hill, 1984.

APPENDICES

Figure 6: Temperature correction factor: one shell pass; two or more even tube passes

Figure 7: Tube side heat transfer factors

Figure 8: Tube side friction factors

Figure 9: Shell side heat transfer factors, segmental baffles

Figure 10: Shell side friction factors, segmental baffles

Figure 11: Heat transfer factors for cross-flow tube banks

Figure 12: Tube row correction factor,

Figure 13: Window correction factor,

Figure 14: Bypass correction factor,

Figure 15: Coefficient for , heat transfer

Figure 16: Friction factors for cross-flow tube banks

Figure 17: Bypass factor for pressure drop,

Figure 18: Coefficient for , pressure drop.

Figure 19: Baffle and tube geometryFigure 20: Baffle geometrical factors

Experiment B: Co-Current Shell & Tube Heat Exchanger

[Fixed Cold Water Flow Rate 10 LPM]1) Calculations of heat transfer and heat lostThe heat transfers of both hot and cold water are both calculated using the heat balance equation.


ii) = 522.58 W

iii) = 1113.93 W

iv) = 1980.31 W

v) = 2612.91 W


ii) = 3887.23 W

iii) = 3401.32 W

iv) = 3193.08 W

v) = 2776.59 W




ii) = =

iii) = =

iv) = =

v) = =

















= = = 3.3 Pa

[Fixed Hot Water Flow Rate 10 LPM]1) Calculations of heat transfer and heat lostThe heat transfers of both hot and cold water are both calculated using the heat balance equation.


ii) = 3850.61 W

iii) = 2819.20 W

iv) = 2681.67 W

v) = 2544.15 W


ii) = 638.62 W

iii) = 1207.82 W

iv) = 1721.49 W

v) = 2637.76 W




ii) = =

iii) = =

iv) = =

v) = =

















= = = 3.3 Pa

b

Documents

heat balance

heat load

introductiona heat exchanger

tube heat exchangerdate

common type of heat

counter flow

parallel flow

cold fluids flow