KNOWN: Long, 30mm-diameter cylinder with embedded electrical heater; power required
to maintain a specified surface temperature for water and air flows.
FIND: Convection coefficients for the water and air flow convection processes, hw and ha,
respectively.
ASSUMPTIONS: Flow is cross-wise over cylinder which is very long in the direction
normal to flow.
The convection heat rate from the cylinder per unit length of the cylinder has
the form
q' = h*(pi*D)*(Ts-Tinf)
and solving for the heat transfer convection coefficient, find
Water
hw = q'/((pi*D)*(Ts-Tinf))
hw = (38*10^3 W/m) / ((pi*(0.030m))*(80-25)C)=
7330.77314 W/m^2K
Air
ha = (400W/m) / ((pi*(0.030m))*(80-25)C)=<span>
77.166033 </span> W/m^2K
COMMENTS: Note that the air velocity is 10 times that of the water flow, yet
hw ≈ 95 × ha.
These values for the convection coefficient are typical for forced convection heat transfer with
liquids and gases
Watter is a better convective heat transfer media than air
Answer:
m = 4.65 kg
Explanation:
As we know that the mass of the water that evaporated out is given as
so the energy released in form of vapor is given as
now the heat required by remaining water to bring it from 15 degree to 100 degree
total heat required for above conversion
now by heat energy balance
heat given by granite = heat absorbed by water
Answer:
m = 0.111 kg
Explanation:
Heat required to release from the body of the person when his temperature cool down by 1 degree C is given as
here we know that
m = 70 kg
s = 3840 J/kg K
now we know that
now the same heat is used to vaporize water of the body
so it is given as
Answer:
Explanation:
I dont know if this will help but A two force member is a body that has forces (and only forces, no moments) acting on it in only two locations. In order to have a two force member in static equilibrium, the net force at each location must be equal, opposite, and collinear.
