Super heated or Saturated Steam

S

Sandeep Shroff

Dear List members

I wanted to know one more thing in continuation to my previous query --

How can I find out the steam is superheated or saturated? Is there an mathematical formula which gives this?

Thanks & Regards

Sandeep Shroff

---- Original message---

Dear List Members,

We are developing a sizing software where we require to calculate the density of saturated and super heated steam. We are in need of an algorithm / developed source code where by we can calculate the density of steam by providing steam pressure & steam temperature ( Just like steam Tables -- infact we are looking for automation of steam tables ).

I would like to get in touch with experts or any directional help / web sites on this.

Thanking you in anticipation.

Warm Regards,

Sandeep Shroff

___________________________________
Sandeep Shroff
Sr. Consultant
Remote & Embedded Technologies

rapidEffect (P) Ltd. 25, Napier Road, Pune 411001, India
Tel./Fax. +91-20-6363250
www.rapideffect.com
__________________________________________________
Web-intelligent solutions for enhanced ROI - get WISER with rapidEffect!

J

Johan Bengtsson

Well, this one is supposed to give the maximum pressure steam could have given the temperature (ie saturated steam).

exp(55.281723-6808.475/T-5.088336*log(T))

Temperature in K and pressure in Pa

I have seen several versions of this formula with different accuracy so you might find someone more accurate. I think this one is pretty good for temeratures around 0-50 deg. C, but you probably want one for higher temperatures (the coeeficients is slightly different)

/Johan Bengtsson

Do you need education in the area of automation?
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Box 252, S-281 23 Hässleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
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J

jmG

1. The latest steam formulas are named IAPWS_97.
Wether you use this version or 1967: is of no cosequential error.

2. NIST will sell the booklet for $90. I have not seen it. 3.Don't use formulas coming out of the blue. 4.Katmare software have a steam properties calculator: very complete. Based on VB. 5. Bernhard Spang from ChemEng offers for free, a very complete VB that you can make an Excel sheet of it. Bernhard uses the IAPWS_97 formulas. I have it. Works perfect (but not actually because I have changed my hard drive and something need be reconfigured). 6. I have same formulation complete runing in Mathcad 8 Pro. They should run in the latest version (2001 Pro) _______________________ Most of these formulas: no instrumentation system will crunch, because they are not math oriented. Formulas pertaining to practical Instrumentation, I made special approximations, lot simpler and extremely accurate (if accuracy means something when original data are statistical in the collection). About your pertaining question: If you know temperature, then you can calculate the saturation pressure and vice versa. Generaly we measure pressure (faster) and calculate saturation temperature. Don't overlook learning about the subject: it roots very deep. I'm willing to complement any kind of information you may need BUT REMEMBER: DETAIL CLEARLY YOUR SUBJECT SO THAT I CAN RECOGNISE_ otherwise I don't open mail. You can come back on same forum. ______________ What about acquiring Mathcad ? Konstantin has the most complete steam/water properties. It sells for about$90. Complete with all graphs included and any kind of units. By the way Katmare has in any units too, but no graph.
Have a good project.

H

Heavner, Lou [FRS/AUS]

I can't find my reference on this, but it seems to me that I used to use the formula: ln P =3D m (1/T) + b for finding vapor pressure of something.
P and T are absolute and m & b can be easily solved for any substance and units.

J

Johan Bengtsson

Yes, I think I have seen that one too, if you look closely you see that they are the same except for the last part. I think the longer form is supposed to be more accurate over a wider range.

/Johan Bengtsson

Do you need education in the area of automation?
----------------------------------------
P&L, Innovation in training
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/
----------------------------------------

J

Johan Bengtsson

Damn, forgot one thing this time too.... This is cut direclty from C source code so log really means ln ie the natural logarithm, not base 10 logarithm

/Johan Bengtsson

Do you need education in the area of automation?
----------------------------------------
P&L, Innovation in training
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/
----------------------------------------

A

Anand

For each different pressure value, there is a saturated temperature.
I believe a temperature above this will make it superheated.

The best source will be steam tables.

Anand

M

Max Morley

Hello Sandeep

Are you still working on the Superheated steam exercise. I see that the date is now very old.

Regards

Max Morley