Application of Double-Duct Idea to Replace Conventional Bell-mouth Intakes

Aims: Controlling specifications of entering flow to a system is a critical issue in preventing any unexpected drop in the system efficiency. To provide the most satisfactory flow stream for internal combustion engines, jet engines, wind tunnels, air conditioning systems, water or oil intakes and thousands of other diverse applications, up until now the main interest was to design or optimize Bell-mouth intakes. Here we propose an innovative approach. Based on a novel idea proposed by Vertical Lift Research Center of Excellence in Pennsylvania State University, this investigation, for the first time, suggests replacing conventional Bell-mouth intakes by a new geometry called Double Duct (D-duct) in order to enhance performance of existing systems
Methodology: With regard to previous investigation, K-epsilon turbulence model was utilized through a Commercial Software package in this numerical investigation. Beside the reliability of the numerical method, which was declared by previous investigators working on similar applications, the method was also validated by comparing it with experimental data gained from one of the research references. An initial configuration of D-duct intake was compared to an elliptical Bell-mouth intake operating on leading edge of a pipe with a pressure intake at its end.
Results: Final results demonstrated nearly 8 percent increase in discharge coefficient and mass flow rate of D-duct system. Close observation of velocity distribution diagrams along the pipe length also proved that there is a noticeable difference between the flow in a conventional Bell-mouth system and a D-duct configuration.
Conclusion: D-Ducts could be used for improving flow characteristics in in-takes and to replace conventional Bell-mouth intake. However due to revolutionary nature of this idea and fundamental changes in the geometry a series of new investigations such for determination of vibration of the second duct etc. would be required.