Answer:
the surface heat-transfer coefficient due to natural convection during the initial cooling period. = 4.93 w/m²k
Explanation:
check attachement for answer explanation
Answer:
6.37 inch
Explanation:
Thinking process:
We need to know the flow rate of the fluid through the cross sectional pipe. Let this rate be denoted by Q.
To determine the pressure drop in the pipe:
Using the Bernoulli equation for mass conservation:

thus

The largest pressure drop (P1-P2) will occur with the largest f, which occurs with the smallest Reynolds number, Re or the largest V.
Since the viscosity of the water increases with temperature decrease, we consider coldest case at T = 50⁰F
from the tables
Re= 2.01 × 10⁵
Hence, f = 0.018
Therefore, pressure drop, (P1-P2)/p = 2.70 ft
This occurs at ae presure change of 1.17 psi
Correlating with the chart, we find that the diameter will be D= 0.513
= <u>6.37 in Ans</u>
Answer:
Activation energy for creep in this temperature range is Q = 252.2 kJ/mol
Explanation:
To calculate the creep rate at a particular temperature
creep rate, 
Creep rate at 800⁰C, 

.........................(1)
Creep rate at 700⁰C


.................(2)
Divide equation (1) by equation (2)
![\frac{0.01}{5.5 * 10^{-4} } = \exp[\frac{-Q}{1073R} -\frac{-Q}{973R} ]\\18.182= \exp[\frac{-Q}{1073R} +\frac{Q}{973R} ]\\R = 8.314\\18.182= \exp[\frac{-Q}{1073*8.314} +\frac{Q}{973*8.314} ]\\18.182= \exp[0.0000115 Q]\\](https://tex.z-dn.net/?f=%5Cfrac%7B0.01%7D%7B5.5%20%2A%2010%5E%7B-4%7D%20%7D%20%3D%20%5Cexp%5B%5Cfrac%7B-Q%7D%7B1073R%7D%20-%5Cfrac%7B-Q%7D%7B973R%7D%20%5D%5C%5C18.182%3D%20%5Cexp%5B%5Cfrac%7B-Q%7D%7B1073R%7D%20%2B%5Cfrac%7BQ%7D%7B973R%7D%20%5D%5C%5CR%20%3D%208.314%5C%5C18.182%3D%20%5Cexp%5B%5Cfrac%7B-Q%7D%7B1073%2A8.314%7D%20%2B%5Cfrac%7BQ%7D%7B973%2A8.314%7D%20%5D%5C%5C18.182%3D%20%5Cexp%5B0.0000115%20Q%5D%5C%5C)
Take the natural log of both sides

Answer:
Change in entropy S = 0.061
Second law of thermodynamics is satisfied since there is an increase in entropy
Explanation:
Heat Q = 300 kW
T2 = 24°C = 297 K
T1 = 7°C = 280 K
Change in entropy =
S = Q(1/T1 - 1/T2)
= 300(1/280 - 1/297) = 0.061
There is a positive increase in entropy so the second law is satisfied.