A thermocouple, with a spherical junction diameter of 0.5 mm, is used for measuring the temperature of hot airflow in a circular
duct. The convection heat transfer coefficient of the airflow can be related with the diameter (D) of the sphere and the average airflow velocity (V) as h = 2.2(V /D)0.5, where D, h, and V are in m, W/m²•K, and m/s, respectively. The properties of the thermocouple junction are k = 35 W/m•K, rho = 8500 kg/m³, and cp = 320 J/kg•K.
If the maximum response time of the thermocouple to record 87 percent of the initially applied temperature difference is 5 s, determine the minimum airflow velocity that the thermocouple can be used.
If the maximum response time of the thermocouple to record 87 percent of the initially applied temperature difference is 5 s, determine the minimum airflow velocity that the thermocouple can be used.
1 answer:
You might be interested in
Answer:
(a) the percent thermal efficiency is 27.94%
(b) the temperature of the cooling water exiting the condenser is 31.118°C
Explanation:
Answer:
ΔQ = 4930.37 BTu
Explanation:
given data
height h = 8ft
Δt = 8 hours
length L = 24 feet
R value = 16.2 hr⋅°F⋅ft² /Btu
inside temperature t1 = 68°F
outside temperature t2 = 16°F
to find out
number of Btu conducted
solution
we get here number of Btu conducted by this expression that s
......................1
here A is area that is = h × L = 8 × 24 = 1492 ft²
put here value we get
solve it we get
ΔQ = 4930.37 BTu