Theory

The theory behind this experiment is to investigate the natural convection from a sphere, using lumped system analysis. A lumped system analysis is used to determine the convective heat transfer of lumped objects, having negligible internal resistance as compared to the external flow resistance, the temperature is assumed to be uniform throughout the object and being a function of time only. By graphing the recorded data points of the experiment, the experimental and theoretical heat transfer coefficients can be found, and those are used to understand the natural convection of the sphere. The mass, specific heat of brass, diameter, area, and kinematic viscosity, are all known values and used to calculate the Nusselt number, Raleigh number, and the heat transfer coefficient at a certain point. The following equations were used to calculate the results in the experiment: y = a1X + a0 a_1=(ΣxiΣyi-nΣxiyi)/((Σxi)^2-nΣxi^2 ); slope A = 〖πD〗^2 h_experimental =

References: 1. Hamid, Rahai., MAE300 LABORATORY EXPERIMENTS, Spring 2013. 2. Hamid, Rahai., MAE300 INSTRUMENTATION AND MEASUREMENTS, Spring 2013. 3. Cengel, Y.A., Heat Transfer, A Practical Approach, McGraw Hill, 1st Edition, 1998. 4. Incorpera, F.P., and De Witt, D.P., Fundamentals of Heat and Mass Transfer, John Wiley&Sons, 4th ed., 1996. 5. Holman, J.P., Heat Transfer, 8th ed. McGraw Hill, 1997.