A multiparametric and fundamental equation of state is presented for the fluid thermodynamic properties of helium. The equation is valid for temperatures from the λ- line (~2.17 K) to 1500 K and for pressures up to 2000 MPa. The formulation can calculate all thermodynamic properties, including density, heat capacity, speed of sound, energies, entropy and saturation properties. A new equation of state is necessary to overcome difficulties associated with the current standard in the asymptotic region between the λ -line and 3 K and also difficulties related to lack of data, extrapolation performance, and accuracy at higher temperatures.
Below 50 K, the uncertainties in density are 0.20% at pressures up to 20 MPa. From 50 K to 200 K the uncertainties decrease to 0.05 % at pressures up to 80 MPa. At higher temperatures the uncertainties in density are 0.02 % up to pressures of 80 MPa. At all temperatures and at pressures higher than listed here, the uncertainties may increase to 0.3% in density. The uncertainties in the speed of sound are 0.02%. The uncertainties in vapor pressure are less than 0.02% and for the heat capacities are about 2%. Uncertainties in the critical region are higher for all properties except vapor pressure.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/151301 |
| Date | 16 December 2013 |
| Creators | Ortiz Vega, Diego O |
| Contributors | Hall, Kenneth R., Holste, James C., Balbuena, Perla, Barrufet, Maria, El-Halwagi, Mahmoud |
| Source Sets | Texas A and M University |
| Language | English |
| Detected Language | English |
| Type | Thesis, text |
| Format | application/pdf |
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