Question
When material properties such as conductivity, density, or viscosity are defined using a Table and the table only covers a finite temperature range, how does Flownex determine the property value when the calculated temperature falls below the lowest temperature in the table or above the highest temperature in the table?
Answer
When material properties are defined using a table, Flownex will interpolate between the specified data points to determine the property value within the defined temperature range. However, if the calculated temperature falls outside the range covered by the table, Flownex does not extrapolate beyond the provided data for the density. viscosity and conductivity.
Instead, Flownex will cap the property value at the nearest available table entry and issue a warning indicating that the temperature is outside the valid range. If the temperature is higher than the maximum temperature in the table, the property will be fixed at the value corresponding to the highest temperature entry. Similarly, if the temperature is lower than the minimum temperature in the table, the property will be fixed at the value corresponding to the lowest temperature entry.
For example, if thermal conductivity is defined from 26°C to 526.85°C and the conductivity at 526.85°C is 38.2 W/m·K, then a calculated temperature of 600°C will result in a conductivity of 38.2 W/m·K, together with an out-of-range warning. Likewise, if the conductivity at 26°C is 51.6 W/m·K, then a calculated temperature below 26°C will result in a conductivity of 51.6 W/m·K, together with an out-of-range warning. Results for the enthalpy and entropy will be extrapolated, but a warning will be given.