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Kohos

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  1. Kohos

    TFS Lindeburg #33

    Thank you! and yes I did notice in the NCEES practice problem we are given all K or equivalent length values
  2. Kohos

    TFS Lindeburg #33

    yes 6.4 was my typo, it should have been 4.6 but I am still not getting the solution values. I opted to use k values, so I have: 5-long radius 90 elbows: 5x0.9 = 3, 1 gate valve - 0.19, 1 sharp edge - 0.5 Total k = 3.69 Total loss = kv2/2g = 14.68 The the 40ft length loss comes to: 9ft so total for me = 26.68ft whereas solution has 16.7 ft following these steps: Book solution: K_entering = 0.5 Effective length with elbow and valve - 40+5*4.6+2.5 = 65.5 Giving total loss of 16.7ft Any advice would be helpful, I was under the assumption that either k or L_eq could be used but now getting different answers, I am not so sure anymore....
  3. Kohos

    TFS Lindeburg #33

    Hello, this is the book: https://ppi2pass.com/pe-mechanical-thermal-and-fluids-systems-practice-exam.html?mkwid=&pcrid=282914701360&pmt=&pkw=&pdv=c&slid=&product=METSPE&gclid=Cj0KCQjw6rXeBRD3ARIsAD9ni9AEuPdVtA214H2xNDVF1Y_Ge-rC_l5N5Vigz4Lbbos5hTap5z21FGQaAtqaEALw_wcB
  4. Kohos

    TFS Lindeburg #33

    Condensed Problem statement: 40ft of 4in sch. 40 steel pipe containing five long radius 90deg. elbows + one gate valve + one sharp edge. V=16ft/s, f=0.019 Book Solution: K_entrance = 0.5 and all others included in the equivalent length as 40ft + 5(6.4ft) + 2.5ft = 65.5 and total head loss calculated as K*v^2/(2g) + f*(65.5)*v2/(2Dg) and answer = 16.7ft My method: K_entrance + K_all others = 0.5+5(0.6)+0.19 = 3.69 and total head loss = v^2/(2g)*(3.69+f*(40)/D) = 23ft I always thought the same answer is achieved whether we take K as a loss or included as an equivalent length, what am I missing here? Thank you
  5. Kohos

    NCEES TFS 508 Problem

    Thank you! I did do those exact steps, went to the compressed tables and couldn't find the answer since it was too low. Appreciate the help from both, will keep this in my notes
  6. Kohos

    NCEES TFS 508 Problem

    Yes, but at 40C, 1MPa>P_sat so wouldn't it still fall under compressed liquid? Hence my confusion.. Thank you!
  7. Kohos

    NCEES TFS 508 Problem

    How do you know whether to read h_f at 1MPa vs. h_f at 40C? Thank you
  8. Thank you! I think I was staring at it for too long, now that I look at the problem again, I see how simple it is. I read it wrong, so grateful for everyone's responses and I hope to return the favor! And thank you for the links, will download the charts
  9. Hi, I tried google and all my references but I don't understand this: on the 13th edition of MERM, example 38.4 has: .....40F (A)dry bulb and 35F (B) wet bulb are mixed ........etc The solution has a specific volume of A as 12.65 ft3/lbm which makes sense. Then it has specific volume of B as 13.68 and I don't know where it came from. I verified the value from this online calculator (http://www.sugartech.co.za/psychro/index.php), but I don't know how it can be read from the graph. Please help! Thanks!
  10. Kohos

    Kohos

    Thank you both!
  11. Kohos

    Kohos

    For those that took the Thermal Fluids Exam in the new format, how much of HVAC topics do you need to know? According to the PPI study guide, it looks like all of MERM's HVAC section is fair play, is this accurate? Thanks in advance
  12. The Thermal study guide listed in the PPI study schedule lists the topics of MERM chapters 40-44 that are labelled under HVAC. Are HVAC topics fair play for the thermal test?
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