Percentage Decrease in Specific Volume using Bulk Modulus from Table

Click For Summary
SUMMARY

The discussion focuses on calculating the percentage decrease in specific volume of water in a hydraulic press subjected to a pressure of 4500 psia, starting from an initial pressure of 15 psia. The correct percentage decrease, as confirmed by the textbook, is 1.34%. The user successfully derived this value by averaging the bulk modulus values (E) at the two pressures, specifically E = [348000 + 320000]/2. This method of averaging is justified as it provides a more accurate representation of the material's response to the pressure change.

PREREQUISITES
  • Understanding of bulk modulus and its application in fluid mechanics
  • Familiarity with specific volume calculations in thermodynamics
  • Knowledge of pressure units, specifically psia (pounds per square inch absolute)
  • Ability to interpret and utilize data from engineering tables
NEXT STEPS
  • Study the principles of bulk modulus in fluid mechanics
  • Learn how to calculate specific volume changes under varying pressure conditions
  • Explore the use of engineering tables for material properties
  • Investigate the relationship between pressure and specific volume in hydraulic systems
USEFUL FOR

Engineering students, hydraulic system designers, and professionals involved in fluid mechanics and thermodynamics will benefit from this discussion.

lizzyb
Messages
167
Reaction score
0
Homework Statement

"Water in a hydraulic press is subjected to a pressure of 4500 psia at 68 F. If the initial pressure is 15 psia, approximately what will be the percentage decrease in specific volume. Use Table 2.1 (below)."

Homework Equations



http://img86.imageshack.us/img86/7606/scanx200908280001.jpg

http://img198.imageshack.us/img198/2330/scanx200908280002.jpg

The Attempt at a Solution



It seems easy enough:

http://img38.imageshack.us/img38/6264/scanx200908280003.jpg

but the back of the book gives 1.34%; what is wrong with my solution?
thx
 
Last edited by a moderator:
Physics news on Phys.org
I came up with the correct solution taking the average value of E at psia = 15 and 4500 (E = [348000 + 320000]/2); how would I justify this?
 

Similar threads

Calculating change in volume (bulk modulus)
  • · Replies 1 ·
Replies
1
Views
4K
How Do I Calculate Bulk Modulus from DFT Data for Solid Carbon Dioxide?
  • · Replies 1 ·
Replies
1
Views
6K