1. The total enthalpy of 15.000kg of steam at 2250.000kPa is 34191.510kJ. Determine the dryness of the steam.
ANS = %
Not sure where to start. I need a little help please. I do have a chart with the properties of saturated steam. Thank you.
To determine the dryness of the steam, you can use the specific enthalpy of saturated steam at the given pressure and compare it to the specific enthalpy of the actual steam.
Here's how you can approach this:
1. Look up the specific enthalpy, h_f, and the specific enthalpy of evaporation, h_fg, at the given pressure of 2250.000 kPa from your chart of saturated steam properties.
2. The specific enthalpy of saturated steam, h, can be calculated using the following equation:
h = h_f + x * h_fg
Where:
h = specific enthalpy of the actual steam
x = dryness fraction (unknown)
h_f = specific enthalpy of saturated liquid water
h_fg = specific enthalpy of evaporation
3. Rearrange the equation to solve for x:
x = (h - h_f) / h_fg
4. Substitute the given values into the equation and calculate x.
For example, if h_f = 191.81 kJ/kg and h_fg = 2263.30 kJ/kg (from the chart), and h = 34191.510 kJ (given in the question), the calculation would be:
x = (34191.510 - 191.81) / 2263.30
Simplifying this would give you the dryness fraction, x, expressed as a decimal. Multiply it by 100 to convert it to a percentage.
Remember to double-check your calculations and units to ensure accurate results.