Answer:
The total tube surface area in m² required to achieve an air outlet temperature of 850 K is 192.3 m²
Explanation:
Here we have the heat Q given as follows;
Q = 15 × 1075 × (1100 - 
) = 10 × 1075 × (850 - 300) = 5912500 J
∴ 1100 - = 1100/3
= 733.33 K
Where
= Arithmetic mean temperature difference
= Inlet temperature of the gas = 1100 K
= Outlet temperature of the gas = 733.33 K
= Inlet temperature of the air = 300 K
= Outlet temperature of the air = 850 K
Hence, plugging in the values, we have;
Hence, from;
, we have
5912500 = 90 × A × 341.67
Hence, the total tube surface area in m² required to achieve an air outlet temperature of 850 K = 192.3 m².
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:
b). The same for all pipes independent of the diameter
Explanation:
We know,
From the above formulas we can conclude that the thermal resistance of a substance mainly depends upon heat transfer coefficient,whereas radius has negligible effects on heat transfer coefficient.
We also know,
Factors on which thermal resistance of insulation depends are :
1. Thickness of the insulation
2. Thermal conductivity of the insulating material.
Therefore from above observation we can conclude that the thermal resistance of the insulation is same for all pipes independent of diameter.
Answer:
$$\begin{align*}
P(Y−X=m|Y>X)=∑kP(Y−X=m,X=k|Y>X)=∑kP(Y−X=m|X=k,Y>X)P(X=k|Y>X)=∑kP(Y−k=m|Y>k)P(X=k|Y>X).
Explanation:
P(Y−X=m|Y>X)=∑kP(Y−X=m,X=k|Y>X)=∑kP(Y−X=m|X=k,Y>X)P(X=k|Y>X)=∑kP(Y−k=m|Y>k)P(X=k|Y>X).
