Compress Exchanger glitch?

[BigTank]

I am working on a floating tube sheet S&T exchanger, and I've noticed a quirk.

Admittedly, I'm not that experienced with the Compress Exchanger module, but it seems that there is a limiter here when it comes to moderate temperatures.

This particular unit has a tube-side design temp. of 1100°F @100PSI, with a shell-side design temp. of 152°F @75PSI. I have had to enter a few yield stresses manually because of this, which was expected.

Here's where the problem comes in: I've entered 3 different calculation (Compres-titled 'design') conditions successfully: the true design spec., the operating conditions, and a shell-side pressure loss. I'm trying to enter the parameters for a 4th situation (tube-side pressure loss), but Compress gives me an error reading:

'All thermal expansion coefficients must be positive....shell coefficient of thermal expansion at tubesheet temperature.'

Now turn to the UHX tubesheet calcs. These thermal expansion coefficients at the entered temperatures appear in the tables for the specified materials that are chosen as reference in the software, but referencing the 'Material Properties' table in the aforementioned calc's, I don't understand where the populated data is coming from. It does not seem to correspond to the entered exchanger conditions. The software doesn't seem to use these coefficients anyway, as I am not calculating for radial thermal expansion. This error is blocking me from entering this 4th condition.

Can anyone shed light?

--------------------------------
Fitter, happier, more productive

 

[BigTank]

Nevermind. I found that this very problem was fixed in build 6262. I need to update.

--------------------------------
Fitter, happier, more productive

 

[BigTank]

Sorry...this is a two-part issue.

So, nevermind the nevermind. I do see that the glitch was fixed, but I would still like to know how the 'Material Properties' table is populated with data...

--------------------------------
Fitter, happier, more productive

 

[TomBarsh]

The material properties come from the referenced tables in ASME or TEMA. For example, ASME yield stresss come from ASME Section II Part D Table Y-1 (which is limited to 1000° F), etc.



"Although this forum is monitored by Codeware it is not intended as a venue for technical support and should not be used as the primary means of technical support."

Tom Barsh
Codeware Technical Support

http://www.codeware.com

 

[BigTank]

That's where I thought the values were coming from, but why do I see this in the UHX calcs (Please excuse the crude tabular format meant to imitate the Compress output.):

Pressures and Temperatures
-----------------------------------------
Tbsht Des T Sh Des T Chan Des T Tube Des T
---------------------------------------------------------
Design ... 1,100 150 1,100 1,100


Material Properties
------------------------------------------
Condition Mean Coeff. Therm. Exp.
------------------------------------------
Design (Shell) 7.50e-06


That particular mean coefficient of thermal expansion is set to come from the ASME TE-1 through TE-5 tables (which terminate at 1300°F for the material in question). The coefficient shown above is for roughly 650°F, which corresponds to none of the input temperatures for any condition set. Such is the case for all components in this unit.

Glitch or am I looking at something wrong?

--------------------------------
Fitter, happier, more productive

 

[TomBarsh]

This forum was never intended for technical support as provided by Codeware.

I suggest that you send your COMPRESS heat exchanger file and your inquiry to support 'at' codeware.com. Or use the online form at

http://www.codeware.com/support/contact.html

"Although this forum is monitored by Codeware it is not intended as a venue for technical support and should not be used as the primary means of technical support."

Tom Barsh
Codeware Technical Support

http://www.codeware.com