145 4875 0270 kjkg k b approximating liquid methane

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: chematic for Example 7–7. Therefore, s s2 s1 5.145 4.875 0.270 kJ/kg · K (b) Approximating liquid methane as an incompressible substance, its entropy change is determined to be s Cav ln T2 T1 (3.4785 kJ/kg · K) ln 120 K 110 K 0.303 kJ/kg · K since Cp, av Cp1 Cp2 3.471 2 3.486 2 3.4785 kJ/kg · K TABLE 7–1 Properties of liquid methane Temp., T, K Pressure, P, MPa Density, r, kg/m3 Enthalpy, h, kJ/kg Entropy, s, kJ/kg · K Specific heat, Cp, kJ/kg · K 110 0.5 1.0 2.0 5.0 425.3 425.8 426.6 429.1 208.3 209.0 210.5 215.0 4.878 4.875 4.867 4.844 3.476 3.471 3.460 3.432 120 0.5 1.0 2.0 5.0 410.4 411.0 412.0 415.2 243.4 244.1 245.4 249.6 5.185 5.180 5.171 5.145 3.551 3.543 3.528 3.486 cen54261_ch07.qxd 11/18/03 9:57 AM Page 295 295 CHAPTER 7 Therefore, the error involved in approximating liquid methane as an incompressible substance is sactual sideal sactual Error 0.270 0.303 0.270 0.122 (or 12.2%) Discussion This result is not surprising since the density of liquid methane changes during this...
View Full Document

This document was uploaded on 11/28/2012.

Ask a homework question - tutors are online