Liquid water at 30.0°C and liquid water at 90.0°C are combined in a ratio (1 kg cold water/2 kg hot water).
(a) Use a simple calculation to estimate the final water temperature. For this part, pretend you never heard of energy balances.
(b) Now assume a basis of calculation and write a closed system energy balance for the process, ne glecting potential and kinetic energy changes and expansion work and assuming that the mixing is adiabatic. Use the balance to calculate the specific internal energy and hence (from the steam tables) the final temperature of the mixture. What is the percentage difference between your answer and that of part (a)?