You can select the FootInch units or Metric Units for the Design. All inputs will be in selected unit system. 
Type Name of txt file in which all process details will be written. 
Select Double Pipe or Tubular Exchanger. 
Flow in Kgs per hour or cubic meters per hour. 
You can select type of Tubular Exchanger. 
Properites of liquids in two streams. 
Physical Properties of two Streams. 
You can select whether Baffles on Shell side required. 
Enter Higher and Lower Values of Heat Transfer Coefficients and Dirt Factor. 
Sizes of Pipes. 
You can select either Square pitch or Triangular pitch.

After Calculating Design Program for Tubular Heat Exchanger shows number of Tubes required. 
here to see Dialog Boxes in Imperial Units
How the Design Program for Tubular Heat Exchanger Calculates?
Design Program for Tubular Heat Exchanger first picks up flow rates, and then inlet and outlet temperatures for Liquid stream. Design Program for Tubular Heat Exchanger also picks up Steam Pressure. Based on Properties of steam at that pressure, Design Program for Tubular Heat Exchanger calculates flow rate of steam. Design Program for Tubular Heat Exchanger also asks for permissible pressure drop on two streams. Design Program for Tubular Heat Exchanger then calculates average temperature of liquid stream. Based on the average temperature, Design Program for Tubular Heat Exchanger asks for specific heat, viscocity and specific gravity of liquid stream.
Liquid stream is generally placed on Shell side and there are no baffles on shell side. Steam is placed on tube side, as steam is more corrosive. The number of passes on tube side is generally an even number (generally 2). You can select Square or Triangular Pitch for tubes.
Design Program for Tubular Heat Exchanger then calculates LMTD. Since steam temperature is same throughout the tube, correction factor for LMTD is not required. Design Program for Tubular Heat Exchanger then asks for expected Higher and Lower value of Overall Heat Transfer Coefficient and value of dirt factor. Design Program for Tubular Heat Exchanger then asks for OD, Pitch, Thickness and Length of tube. Based on these, calculation is done. Initially programs assumes number of tubes equal to number of passes. Based on this tube count, Design Program for Tubular Heat Exchanger assigns shell diameter (as per number of passes)
Calculation of number of Tubes:
For Shell: Design Program for Tubular Heat Exchanger calculates Mass Velocity for shell by dividing shell side mass flow rate by shell cross sectional area. Design Program for Tubular Heat Exchanger then calculates equivalent diameter of tube. Based on this Design Program for Tubular Heat Exchanger calcuates Reynold's number. Based on Reynold's number, Design Program for Tubular Heat Exchanger picks up value of j_{H} for shell automatically. Design Program for Tubular Heat Exchanger then calculates Overall Heat Transfer Coefficient, h_{o} for outer side of tube.
For Tubes: Design Program for Tubular Heat Exchanger calculates Mass Velocity for tube by dividing tube side mass flow rate by cross sectional area of tube. Based on this Design Program for Tubular Heat Exchanger calcuates Reynold's number based on inner diameter of tube. Design Program for Tubular Heat Exchanger then assigns Overall Heat Transfer Coefficient, h_{io} for inner side of tube.
Design Program for Tubular Heat Exchanger then corrects the two values for viscocity of liquids at wall temperature. Overall Heat Transfer Coefficient is then calculated based on h_{o}, h_{io} and dirt factor. The heat transfer area required is calculated by dividing heat load by LMTD and value of Overall Heat Transfer Coefficient. Dividing heat transfer area by tube's outer surface area gives the number of tubes required. If calculated tubes are more than number of tubes assumed, Design Program for Tubular Heat Exchanger increases number of tubes assumed by one and recalculates. Design Program for Tubular Heat Exchanger follows this procedure till number of assumed tubes are same as number of calculated tubes.
Calculation Pressure Drop:
For Tube: Based on Reynold's number calculated earlier, Design Program for Tubular Heat Exchanger picks up value of friction factor. Design Program for Tubular Heat Exchanger picks up density of steam at that presure. Based on these, Design Program for Tubular Heat Exchanger calculates pressure drop.
For Shell: Based on Reynold's number calculated earlier, Design Program for Tubular Heat Exchanger picks up value of friction factor. Based on that, Design Program for Tubular Heat Exchanger calculates pressure drop.
If the pressure drops on both sides is within limit, design is good. Otherwise new combination of OD, Pitch, Thickness and Length of tube is tried to get the result.
Report Generated by Design Program for Tubular Heat Exchanger
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*Process Design
Units of Calculation : Imperial
Input Values in Metric system
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Type : Shell and Tube Heat Exchanger
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Duty : Heating Chemical by Steam
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*Input Parameters
Shell side flow rate : 90744.00 kg/h
Shell side inlet Temp : 50.00 Deg C
Shell side outlet Temp : 37.77 Deg C
Shell side Allowable Pressure Drop : 0.70 Kg/sq.cm.
Shell side liquid Specific Heat : 0.8614 Btu/lbDeg F
Shell side liquid Viscosity : 1.30 cP
Shell side Specific Gravity : 1.8000
Tube side Steam Pressure : 2.27 kg/sq cm
Tube side Steam Temp : 108.87 Deg C
Tube side liquid Viscosity : 0.0127 cP
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Liquid on Shell side
Steam on Tube side
Number of Tube Side Passes : 2
Dirt Factor Rd : 0.0030
Heat Transfer Load : 3792567.67 Btu/hr
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*Tube Data
Tube Outer Diameter : 19 mm
Length of Tube : 4800 mm
Tube Thickness BWG : 16
Tube Pitch : 25 mm
Tube Configration : Square
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*All Calculations done in Imperial Units
Tube Side Flow Area : 0.0765 sq. ft.
Tube Side Mass Velocity : 51603.55 ft/h
Tube Side Reynold's Number : 86750
Tube Side mean Temp : 227.96 Deg F
Tube side Heat Transfer Coefficient h : 1500 Btu/hsq. ft. Deg F
Shell Side Flow Area : 0.5614 sq. ft.
Shell Side Mass Velocity : 356228.37 ft/h
Shell Side Reynold's Number : 17740
Shell Side jH value : 57.5000
Shell Side mean Temp : 110.99 Deg F
Shell side c Value : 1.30
Shell side k Value : 0.33
Shell side Heat Transfer Coefficient h : 281.96 Btu/hsq. ft. Deg F
Shell side Heat Transfer Coefficient h (corrected for viscocity) : 283.20 Btu/hsq. ft. Deg F
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Number of Tubes : 74
Recommended Shell NB : 300 mm
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*Pressure Drop Calculations in Imperial Units
Shell side Pressure Drop
Shell Side Reynold's Number : 17740
Shell side Friction Factor : 0.0019
Shell side Mass Velocity : 356228.37 ft/h
Shell ID : 1'
Shell Liquid specific gravity : 1.8000
Equivalent Dia of Tube : 1
Shell side Pressure Drop : 0.0040 kg/sq cm

Tube side Pressure Drop
Tube Side Reynold's Number : 86750
Tube side passes : 2
Tube side Friction Factor : 0.0002
Tube Liquid specific gravity : 0.0008
Tube Side Mass Velocity : 51603.55 ft/h
Length of Tube : 4800 mm
Inside Dia of Tube : 1
Tube side Pressure Drop : 0.2092 kg/sq cm
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Summary
Type : Shell and Tube Heat Exchanger
Tube Outer Diameter : 19 mm
Length of Tube : 4800 mm
Number of Tubes : 74
Tube Thickness BWG : 16
Tube Pitch : 25 mm
Number of Tube Side Passes : 2
Tube Configration : Square
Recommended Shell NB : 300 mm
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