TFS · Practice Exam 1 · Problem 79 PDF Solution in PDF ↓
TFS · Practice Exam 1 · Problem 79
Problem & Solution
PDF: Practice Exam #1-79.pdf
Video Synthesis
  • - Problem: 25 GPM of water at 300 PSIA and 250 degrees goes through a boiler where it's converted to 500 PSIA steam at a thousand degrees.
  • - Key values: 300 PSIA, 500 PSIA, 500 psi, 33000 in
  • - Reference: steam table, look up
  • - Result: The one substitution I will make is that in terms of Q dot equals m dot delta H of course we could work on the side and figure out what the mass flow ...
  • - ✅ Answer: B
Office Hours 1
Student questions asked in live office hours about this problem
OH 98
Q: In problem 1-79, why is the assumption that subcooled liquid density equals saturated liquid density valid, and would we be expected to make this assumption on the PE exam?
A: Water is treated as incompressible in most PE problems, which justifies this assumption—it's defensible within 5% engineering tolerance. However, you correctly identified that water is slightly compressible; your research showing a 4.3% density change over 180°F is solid, but the real issue here is that the answer choices were too close together, not that the assumption was wrong.
MPEP OH Prep Dashboard Problem 79 · Practice Exam 1 PDF-Embedded Format