Answer to Question #228856 in Molecular Physics | Thermodynamics for Thorfinn

Question

The flow energy of 142 liters/min of a fluid passing a boundary to a system is 108.5 kJ/min. Determine the pressure at this point. 

p = ___ kPa

Answer in 2 decimal places

Answer 1

Energy flow Q = 142 L/min

Boundary to system P= 108.5 kJ/min

$P= \frac{108.5 \times 10^3\;J}{60\;sec} \\ P= 1808.3 \;W \\ P=1.81 kW$

We know that,

$P= \frac{Work \; done \;(W)}{Time \; (t)} = \frac{Force \times distance}{Time} \\ P= Force \; (F) \times V \\ Velocity \; V = \frac{distance}{Time} \\ P=P_1 \times A \times V \\ Pressure \;(P_1) = \frac{F}{A} \\ P = P_1 \times Q \\ Energy \; flow \; Q = A \times V$

Putting values

$P_1 = \frac{P}{Q} = \frac{1.81 \;kW \times 60 \;sec}{0.142\;m^3/min} \\ = 764.78 \;kPa$

Answer: 764.78 kPa