Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2023 - September 06, 2023
Jet fans are considered as simple components to boost the tunnel ventilation. But they contain some important and complex aspects in them. First, the authors discuss the principle of pressure gaining mechanism in tunnels by jet fans, which was established by Meidinger. Then, a sample calculation of overall efficiency by a jet fan is carried out for a typical case to show it’s just less than 20% with the reason why it takes such low values. Next, problems with the measurement of jet fan performances are discussed. The authors point out inaccuracy of measurement of the discharged air velocities with Pitot tubes and suggest the specification introducing thrust forces be more appropriate to define. Finally, the importance of commissioning on ventilation systems is stressed, and is urged to study it for the adoption.
