An empty cannister of 0.002 m3 is filled with R-134a from a line flowing saturated liquid R-134a at 0°C. The filling is done quickly so it is adiabatic, but after a while in storage, the can warms up to room temperature, 20degC. Find the final mass in the cannister and the total entropy generation.
I found that the final mass is 2.32kg and that will stay constant even while the can warms up. However, I'm not sure if the final temperature of the can at 20deg will effect the final entropy.
To find the final mass in the canister, you can use the ideal gas law combined with the specific volume of the R-134a at the initial and final temperatures.
1. Initial state: The canister is filled with saturated liquid R-134a at 0°C. From the given information, the specific volume of R-134a at this state can be determined.
2. Final state: The canister warms up to room temperature, 20°C. To calculate the final mass, we need to find the specific volume of R-134a at this state.
- Start by determining the specific volume of R-134a at the initial state. Use tables or online resources to find the value. Let's call it v1.
- Similarly, find the specific volume of R-134a at the final state. Let's call it v2.
- Since the canister is adiabatic, the mass of R-134a remains constant. Let's call it m.
Now, using the ideal gas law, we can relate the mass, specific volume, and temperature of the gas:
m = (v1 * m1) / (v2 * m2)
Where m1 represents the initial mass and m2 represents the final mass. Rearranging the equation:
m2 = (v2 * m1) / v1
Substituting the given values, you can calculate the final mass.
Now, regarding the total entropy generation, the change in entropy can be calculated using the formula:
ΔS = m * (s2 - s1)
Where s1 and s2 represent the initial and final specific entropy values, respectively. To find these values, you can use tables or online resources specific to R-134a at the respective temperatures.
Calculate the change in entropy and that will give you the total entropy generation.