Package Regions contains a large number of auxiliary functions which are needed to compute the current region of the IAPWS/IF97 for a given pair of input variables as quickly as possible. The focus of this implementation was on computational efficiency, not on compact code. Many of the function values calculated in these functions could be obtained using the fundamental functions of IAPWS/IF97, but with considerable overhead. If the region of IAPWS/IF97 is known in advance, the input variable mode can be set to the region, then the somewhat costly region checks are omitted. The checking for the phase has to be done outside the region functions because many properties are not differentiable at the region boundary. If the input phase is 2, the output region will be set to 4 immediately.
The main 4 functions in this package are the functions returning the appropriate region for two input variables.
In addition, functions of the boiling and condensation curves compute the specific enthalpy, specific entropy, or density on these curves. The functions for the saturation pressure and temperature are included in the package Basic because they are part of the original IAPWS/IF97 standards document. These functions are also aliased to be used directly from package Water.
All other functions are auxiliary functions called from the region functions to check a specific boundary.
| Name | Description |
|---|---|
| boundary23ofT | Boundary function for region boundary between regions 2 and 3 (input temperature) |
| boundary23ofp | Boundary function for region boundary between regions 2 and 3 (input pressure) |
| hlowerofp5 | Explicit lower specific enthalpy limit of region 5 as function of pressure |
| hupperofp5 | Explicit upper specific enthalpy limit of region 5 as function of pressure |
| slowerofp5 | Explicit lower specific entropy limit of region 5 as function of pressure |
| supperofp5 | Explicit upper specific entropy limit of region 5 as function of pressure |
| hlowerofp1 | Explicit lower specific enthalpy limit of region 1 as function of pressure |
| hupperofp1 | Explicit upper specific enthalpy limit of region 1 as function of pressure (meets region 4 saturation pressure curve at 623.15 K) |
| slowerofp1 | Explicit lower specific entropy limit of region 1 as function of pressure |
| supperofp1 | Explicit upper specific entropy limit of region 1 as function of pressure (meets region 4 saturation pressure curve at 623.15 K) |
| hlowerofp2 | Explicit lower specific enthalpy limit of region 2 as function of pressure (meets region 4 saturation pressure curve at 623.15 K) |
| hupperofp2 | Explicit upper specific enthalpy limit of region 2 as function of pressure |
| slowerofp2 | Explicit lower specific entropy limit of region 2 as function of pressure (meets region 4 saturation pressure curve at 623.15 K) |
| supperofp2 | Explicit upper specific entropy limit of region 2 as function of pressure |
| d1n | Density in region 1 as function of p and T |
| d2n | Density in region 2 as function of p and T |
| dhot1ofp | Density at upper temperature limit of region 1 |
| dupper1ofT | Density at upper pressure limit of region 1 |
| hl_p_R4b | Explicit approximation of liquid specific enthalpy on the boundary between regions 4 and 3 |
| hv_p_R4b | Explicit approximation of vapour specific enthalpy on the boundary between regions 4 and 3 |
| sl_p_R4b | Explicit approximation of liquid specific entropy on the boundary between regions 4 and 3 |
| sv_p_R4b | Explicit approximation of vapour specific entropy on the boundary between regions 4 and 3 |
| rhol_p_R4b | Explicit approximation of liquid density on the boundary between regions 4 and 3 |
| rhov_p_R4b | Explicit approximation of vapour density on the boundary between regions 4 and 2 |
| boilingcurve_p | Properties on the boiling curve |
| dewcurve_p | Properties on the dew curve |
| hvl_p | |
| hl_p | Liquid specific enthalpy on the boundary between regions 4 and 3 or 1 |
| hv_p | Vapour specific enthalpy on the boundary between regions 4 and 3 or 2 |
| hvl_p_der | Derivative function for the specific enthalpy along the phase boundary |
| rhovl_p | |
| rhol_p | Density of saturated water |
| rhov_p | Density of saturated vapour |
| rhovl_p_der | |
| sl_p | Liquid specific entropy on the boundary between regions 4 and 3 or 1 |
| sv_p | Vapour specific entropy on the boundary between regions 4 and 3 or 2 |
| rhol_T | Density of saturated water |
| rhov_T | Density of saturated vapour |
| region_ph | Return the current region (valid values: 1,2,3,4,5) in IF97 for given pressure and specific enthalpy |
| region_ps | Return the current region (valid values: 1,2,3,4,5) in IF97 for given pressure and specific entropy |
| region_pT | Return the current region (valid values: 1,2,3,5) in IF97, given pressure and temperature |
| region_dT | Return the current region (valid values: 1,2,3,4,5) in IF97, given density and temperature |
| hvl_dp | Derivative function for the specific enthalpy along the phase boundary |
| dhl_dp | Derivative of liquid specific enthalpy on the boundary between regions 4 and 3 or 1 w.r.t. pressure |
| dhv_dp | Derivative of vapour specific enthalpy on the boundary between regions 4 and 3 or 1 w.r.t. pressure |
| drhovl_dp | |
| drhol_dp | Derivative of density of saturated water w.r.t. pressure |
| drhov_dp | Derivative of density of saturated steam w.r.t. pressure |