Dear experts,
As I calculated isothermal compressibility coefficient of thermal expansion in pipe, the result seems negative (minus) number. As API 521, isothermal compressibility coefficient is
X = 1/v1 (v1-v2)/(p2-p1)
X = the isothermal compressibility coefficient, expressed in 1/kPa (1/psi)
v1 = the specific volume of liquid at the first pressure, expressed in m3/kg (ft3/lb)
v2 = the specific volume of liquid at the second pressure, expressed in m3/kg (ft3/lb)
p1 = the first absolute pressure, expressed in kPa (psi)
p2 = the second absolute pressure, expressed in kPa (psi)
The conditions I've calculated are showen below.
roh at T1 = 1046.8 kg/m3
roh at T2 = 1045.5 kg/m3
DeltaT = 1 degC (assume)
v1 at T1 =0.00095530 m3/kg
v2 at T2 =0.00095649 m3/kg
p1 = 70 kPa (Actual)
p2 = 653 kPa (Actual)
x = -0.000021
It means T2 is lower than T1. But P2 is higher than P1. What am I wrong? I am still struggling to understand. Please correct me where I am wrong. Thank you!