Abstract:
The purpose of performing this experiment is to determine experimentally the relationship between the Nusselt number and Reynolds number for a heated cylinder that is subject to cooling by a cross flow of air and then performs a comparison with correlations that are provided in the referenced textbook.
The experiment is performed through different variations that act as a restrictor to pressure and free stream velocity in addition to changes in voltage settings. The data is transferred into a table and going across a table from the open end up to plate 3, flow becomes more restricted, decreasing the pressure and free stream velocity (U∞).TheNusselt number(NuD) also decreased as it is directly proportional to Reynolds Number(Re). Reynolds Number encountered a decrease as flow becomes more restricted due to the direct proportionality with the free stream velocity.
The lowest percentage change in the value of NuD is calculated to be 12.3% and a trend can be seen as the voltage increases, the error in Nusselt number increases. The largest percentage change in the value of NuD experimentally in comparison to the theoretical value provided by the correlation in the textbook is calculated to be 23.7% at the voltage setting of 65V. This is based on the average value for the Nusselt number through the four different applications of the plates.
The experiment does show a significant and noticeable error between the experimental power law equations to the theoretical power law equation. The two equations were curve fitted based on the provided data experimentally and theoretically using equations provided by the text. The largest error in the ratio of NuD to Pr1/3is calculated to be 49.2%. This provides an explanation to why the curve fitted plot experimentally shown in the figures in the data and results section do have a deviation from the theoretical correlation. Although the deviation is clear, the results seems valid as it is expected due to the consideration of the elevation of the manometer to be equal to zero and the consideration of the heat by radiation to be negligible along with other assumptions.
Attachment:- Lab Assignment.rar