Answer:
Shell length in the heat exchanger is derived from the tube length value entered in the Bundle tab in Shell and Tube Heat Exchanger Properties dialog box.
Consider the following example.
For the BEU type exchanger, the entered value of tube length is 2800 mm
The value of shell length is kept blank:
The user can specify a value of the shell but it is not necessary as software calculates it. However please make sure that the shell length is consistent.
The tube length field is mandatory and a value must be entered.
The length of the tube (2800 mm) is only the length of the straight portion of the tube.
The length of the shell is calculated by the program by taking into account many parameters as per the following:
1.The length of the bend portion of the tube, the largest U-Tube centerline is aligned with the tangent line
2.The straight length of the tube (2800 mm in this case)
3.The length of the body flange and flange gasket assembly
4.The gasket thickness
5.The tubesheet thickness, and how it is assembled with the flange
6. The tube extension, as specified in the tubesheet
After factoring all these the length of the shell is calculated as 2876 mm in this case
Following is the explanation of the shell length calculations:
Refer to the 2d sketch generated:
The calculations of the shell length explained below:
Obtain the largest bend radius from bend summary in the design report, 342.5 mm in this case:
As mentioned above the centerline of the tube aligns with the vessel reference tangent line.
Now refer to the calculations below for shell length:
To understand how the calculated value of 213 is determined refer to the tube sheet geometry, machined ext. and tube extension, gasket thickness, flange, tubesheet thickness etc.
The value of 2876.5 matches with the value in geometry list (rounded-off to 2876)
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