2. Find the heat flux from the surface of 1 meter of uninsulated gas pipe with an inner diameter of 1000 mm, a wall thickness of 10 mm , having a thermal conductivity (steel) of 50W/(mcdot K) Gas temperature inside the gas pipe is 70^circ C , and that of the ambient air is 5^circ C Heat transfer coefficients are: from gas to pipe wall 300W/(m^2cdot K) from pipe to air 15W/(m^2cdot K)

To find the heat flux from the surface of the gas pipe, we can use the concept of heat transfer through conduction, convection, and radiation. The heat flux can be calculated using the following formula:<br /><br />q = (h1 * (T1 - T2)) + (h2 * (T2 - T3))<br /><br />where q is the heat flux, h1 is the heat transfer coefficient from gas to pipe wall, T1 is the gas temperature, T2 is the pipe wall temperature, h2 is the heat transfer coefficient from pipe to air, and T3 is the ambient air temperature.<br /><br />First, we need to calculate the pipe wall temperature (T2) using the formula:<br /><br />T2 = (h1 * T1) / (h1 + h2)<br /><br />Substituting the given values, we get:<br /><br />T2 = (300 * 70) / (300 + 15) = 68.18°C<br /><br />Now, we can calculate the heat flux using the formula:<br /><br />q = (300 * (70 - 68.18)) + (15 * (68.18 - 5)) = 300 * 1.82 + 15 * 63.18 = 546 + 945 = 1491 W/m²<br /><br />Therefore, the heat flux from the surface of the gas pipe is 1491 W/m².