Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Recent content by jhartis

  1. jhartis

    Temperature Increase in Pipeline

    You might want to check out the NAIMA 3E Plus software. Its free and does heat loss calcs for insulated and bare pipes, etc. Did I mention its free? http://www.pipeinsulation.org/pages/download.html
  2. jhartis

    Gas Cooling on Expansion

    25362, et al I'm struggling with much of this, but you say that for constant kinetic energy, delta H = 0. But there is a large velocity change, as denniskb mentions, the velocity is likely sonic at the restriction and perhaps again at the discharge on the expansion to atmosphere (for cases...
  3. jhartis

    Gas Cooling on Expansion

    denniskb, Cool, I am impressed with your work. FYI, I used a standard presta bicycle valve on the bottle which probably has an ID around 4 mm, but it has a valve stem which reduces the area of the exit. I didn't time the blowdown, but it seemed to be about 2 or 3 sec, as well as I can...
  4. jhartis

    Gas Cooling on Expansion

    denniskb: You ask if I sensed the cold of the bottle or the gas. The bottle was ambient (summer) temperature at pressure. I let it cool for a while for the heat of compression to dissipate before releasing the pressure. As the gas was released, the exiting gas was noticeably cool. The...
  5. jhartis

    Check if Sheet exists

    There may be a better way, but exists = False For Each wkSheet in Thisworkbook.Worksheets if wkSheet.Name = "Sheet4" Then exists = True End If Next If exists = False then Thisworkbook.Sheets.Add Before:= _ Worksheets(Worksheets.Count)...
  6. jhartis

    Intermittent Remove Module Problem

    I am having a problem removing modules via VBA code. code snippet... WkBook = "Book1.xls" ModName = "Module1" Workbooks(WkBook).VBProject.VBComponents.Remove _ Workbooks(WkBook).VBProject.VBComponents.(ModName) This works sometimes (especially in single step mode), but other times it doesn't...
  7. jhartis

    Gas Cooling on Expansion

    Thanks to all. While some of these posts help, I'm still a little confused. To answer Quarks question about the pressure capability of a Coke bottle, I pumped a standard 2 liter PET Coke bottle to nearly 150 psi, before I chickened out and quit pumping. I see now that I really have 2...
  8. jhartis

    Gas Cooling on Expansion

    In calculating downstream temperatures in a 50 psig compressed air system, I cane across an apparent puzzle. I know the Joule Thomson coefficient for air at my conditions is roughly 0.25 °C/atm so an expansion from 3 atm -> 1 atm should cool a little less than 1°C (correct?). I did an...
  9. jhartis

    Cooling coil corrosion in 316L reactor

    A test coupon of 316SS may be useful to see if the problem is material or process related
  10. jhartis

    Babcock Formula

    Can anyone give me the 'Babcock Formula' for steam pressure loss? I checked my copy of Babcock & Wilcox and Crane plus intternet searches, but no luck.
See more

Part and Inventory Search

Back
Top