Part 1: Two streams of water (state 1 and state 2) mix together and form a singl

Question

Part 1:

Two streams of water (state 1 and state 2) mix together and form a single stream (state 3).

State 1: mass flow 1=1 kg/s T1=15C P1 = 1 bar
State 2: mass flow 2=4 kg/s T1=20C P2 = 1 bar

Assume that the stream is heated at a rate of 2 kW
Assume that the stream has a pressure of 1 bar at state 3.

1. Solve for the temperature at state 3
2. Solve for the entropy production

Part 2: Two streams of water (state 4 and state 5) mix together and form a single stream (state 6).

State 4: mass flow 4=1 kg/s T4=15C P4 = 1 bar
State 5: mass flow 5=4 kg/s T5=15C P5 = 2 bar

Assume that the stream is heated at a rate of 2 kW
Assume that the stream has a pressure of 1 bar at state 3.

Using EES:

1. Solve for the temperature at state 3
2. Solve for the entropy production

Which causes more entropy production, a 5C temp difference, or a 1 bar pressure difference?

Explanation / Answer

At state 3

temperature=25C(by interpolation)

Entropy can be calculated as:

Using steam table see value oentropy at 1 bar and 25 C and then you will get correct value..!!!

Plz..do rate my answer with 5 star ratings..!!!

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