Posted by Danny on Saturday, July 13, 2013 at 9:42am.

1. The total enthalpy of 15.000kg of steam at 2250.000kPa is 34191.510kJ. Determine the dryness of the steam.
ANS = %

2. Determine the quantity of heat required, to raise 11.100kg of water at 80.000 degrees Celsius, to saturated steam at 2250.000kPa and 71.400% dry.
ANS = kJ

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 solve these questions, we need to use the properties of saturated steam and apply the laws of thermodynamics.

First, let's tackle question 1:

1. The total enthalpy of the steam is given as 34191.510 kJ.

To determine the dryness of the steam, we need to use the equation:

H = h + x * h_fg

Where:
- H is the total enthalpy of the steam
- h is the specific enthalpy of the liquid portion of the steam
- x is the dryness fraction (which we need to find)
- h_fg is the specific enthalpy of vaporization

We can find the specific enthalpy of vaporization from the properties of saturated steam chart.

Now let's move on to question 2:

2. We need to determine the quantity of heat required to raise water from 80.000 degrees Celsius to saturated steam at 2250.000 kPa and 71.400% dry.

To solve this, we need to consider the three stages involved:

Stage 1: Heating water from its initial temperature to the boiling point:
- We can use the equation:

Q1 = m * Cp * (T2 - T1)

Where:
- Q1 is the quantity of heat required
- m is the mass of water
- Cp is the specific heat capacity of water
- T2 is the final temperature (the boiling point)
- T1 is the initial temperature

Stage 2: Vaporizing the water at the boiling point:
- We can use the equation:

Q2 = m * h_fg

Where:
- Q2 is the quantity of heat required
- m is the mass of water
- h_fg is the specific enthalpy of vaporization

Stage 3: Heating the resulting steam to the final state:
- We can use the equation:

Q3 = m * Cp * (T3 - T2)

Where:
- Q3 is the quantity of heat required
- m is the mass of steam
- Cp is the specific heat capacity of steam
- T3 is the final temperature (2250.000 kPa and 71.400% dry)

Finally, to find the total quantity of heat required, we sum up the three stages:

Q_total = Q1 + Q2 + Q3

By plugging in the given values and using the properties of saturated steam, we can find the answer to both questions.