In this chapter, we will discuss the concept of free convection, which is a type of heat transfer that occurs when a fluid is in contact with a surface at a different temperature. We will derive the governing equations for free convection and discuss the various correlations used to predict the heat transfer coefficient.
Using the wrong correlation for a horizontal plate versus a vertical one will lead to significant errors. In this chapter, we will discuss the concept
For a cylindrical heater in air or water, the solution involves: : Nusselt Correlation : For a cylindrical heater in air or water,
: Compute the Rayleigh number using the characteristic length ( Lccap L sub c Instead of just throwing numbers at a formula,
A 10-cm-diameter, 20-cm-long cylinder is maintained at a temperature of 100°C in a large room where the temperature is 20°C. The heat transfer coefficient in free convection is to be determined.
Cengel’s manuals are famous for their "Assumption, Analysis, and Discussion" format. Instead of just throwing numbers at a formula, the solutions explain a specific Nusselt number correlation was chosen. Clarity of Properties: A major plus is how the manual lists the fluid properties
$$ Ra_L = \fracg \beta (T_s - T_\infty) L^3\nu^2 Pr $$