Question

A 300-ft long section of a steam pipe with an outside diameter of 4 in passes through an open space at 50oF. The average temperature of the outer surface of the pipe is measured to be 280oF, and the average convection heat transfer coefficient between the pipe and surrounding air is estimated to be 6 Btu/h·ft 2·oF. Determine the rate of heat loss from the pipe by convection

Answer 1

Answer:

The rate of heat loss from the pipe by convection is 433113 Btu/h

Explanation:

Given that:

The length of the steam pipe = 300 ft

Temperature of the open space $T_{air$ = 50 ° F

Outside diameter = 4 ㏑ = 4/12 ft = 0.333 ft

Avg, temperature of the surface of the pie $T_s$ = 280° F

Avg. convection of heat transfer h  = 6 Btu/h·ft²·°F

We are to Determine the rate of heat loss from the pipe by convection

Let first calculate the area of the heat transfer;

A = πdh

A =  πdL

A = π× 0.333 ft ×300 ft

A = 313.85 ft²

The rate of heat loss  from the pipe by convection can now be calculated by using the formula:

$Q_{pipe} = hA ( T_s - T_{air})$

Replacing our values from above ; we have:

$Q_{pipe} = 6* 313.85 ( 280 -50})$

$Q_{pipe} = 1883.1*( 230})$

$\mathbf{Q_{pipe} =433113 \ \ Btu/h }$

Therefore, the rate of heat loss from the pipe by convection is 433113 Btu/h