Answer:
I=0.3636
Explanation:
See the attached picture for explanation.
Answer:
Mechanical Efficiency = 83.51%
Explanation:
Given Data:
Pressure difference = ΔP=1.2 Psi
Flow rate = 
Power of Pump = 3 hp
Required:
Mechanical Efficiency
Solution:
We will first bring the change the units of given data into SI units.

Now we will find the change in energy.
Since it is mentioned in the statement that change in elevation (potential energy) and change in velocity (Kinetic Energy) are negligible.
Thus change in energy is

As we know that Mass = Volume x density
substituting the value
Energy = Volume * density x ΔP / density
Change in energy = Volumetric flow x ΔP
Change in energy = 0.226 x 8.274 = 1.869 KW
Now mechanical efficiency = change in energy / work done by shaft
Efficiency = 1.869 / 2.238
Efficiency = 0.8351 = 83.51%
Answer:
the rate of heat loss by convection across the air space = 82.53 W
Explanation:
The film temperature

to kelvin = (5 + 273)K = 278 K
From the " thermophysical properties of gases at atmospheric pressure" table; At
= 278 K ; by interpolation; we have the following
→ v 13.93 (10⁻⁶) m²/s
→ k = 0.0245 W/m.K
→ ∝ = 19.6(10⁻⁶)m²/s
→ Pr = 0.713

The Rayleigh number for vertical cavity

= 
= 

For the rectangular cavity enclosure , the Nusselt number empirical correlation:





h = 1.99 W/m².K
Finally; the rate of heat loss by convection across the air space;
q = hA(T₁ - T₂)
q = 1.99(1.4*0.96)(20-(-10))
q = 82.53 W