Pages: 20 to 29
Bahgat K. Morsy, Fahad Al-Mufadi and A.E. Abdelraheim
An experimental loop was designed and constructed in order to simulate air duct systems usually adopted in industrial processes. In this work, the loop consisted of two main branches; each branch could be fixed at desired angle of inclination ranging from to from the axis of the main duct. The losses of energy due to pressure drop through the duct were measured at different points through the loop. Experiments were performed at different flow rates with various air exits at Reynolds number between and . The objectives of the present work are to predict the pressure losses through air in the variable volume control system as well as to determine the optimum angle of inclination to cause minimum pressure drop. It has been found that the percentage of the air exit opening and the degree of inclination of branched duct have significant influence on the energy losses due to the pressure drop. Results from the present study showed that with an angle of 90o and a full exit opening as well as with an angle of 15o and 75% of the exit opening, the pressure drop reached its minimum value. This can be attributed to the existence of the secondary flow within the elbow. It was also observed that more narrowing of air exit resulted in increased generation of back pressure inside the duct at different sections. This significant observation makes it possible to rely upon the design of the present loop when the air variable volume control system is utilized in industry.