2. Determine the heat transfer coefficient and the linear heat flux in the transverse air flow for a pipe with a diameter of d=80mm if its surface temperature is t_(s)= 80^circ C the air temperature is t_(a)=8^circ C and the wind speed is w=3m/s

To determine the heat transfer coefficient and the linear heat flux in the transverse airflow for a pipe, we can use the Dittus-Boelter equation, which is a commonly used empirical correlation for convective heat transfer. The Dittus-Boelter equation is given by: where:- is the heat transfer coefficient,- is the Reynolds number,- is the Prandtl number,- is the characteristic length (in this case, the diameter of the pipe),- is the diameter of the pipe.First, we need to calculate the Reynolds number ( ) and the Prandtl number ( ): where is the kinematic viscosity of air at the film temperature (which is approximately the average of the air and surface temperatures). At , the kinematic viscosity of air is approximately . Next, we calculate the Prandtl number: where is the specific heat capacity of air at the film temperature, and is the thermal conductivity of air at the film temperature. At , the specific heat capacity of air is approximately \( c_p = 1005 J/(kg \cdot K) \), and the thermal conductivity of air is approximately \( k = 0.03 W/(m \cdot K) \). Now, we can calculate the heat transfer coefficient: Finally, we can calculate the linear heat flux: Therefore, the heat transfer coefficient is approximately \( 38,000 W/(m^2 \cdot K) \), and the linear heat flux is approximately .