Numerical Investigation of synthetic impinging jets at low orifice-plate distances

Thesis Type: Postgraduate

Institution Of The Thesis: Gazi University, Mühendislik Fakültesi, Turkey

Approval Date: 2022

Thesis Language: Turkish

Student: Eda Ergür

Supervisor: Tamer Çalışır


There are experimental and theoretical studies on synthetic impingement jets in the literature. Synthetic impingement jets have zero net mass flux and are widely used because of the use of the surrounding fluid. These synthetic jets allow to improve heat transfer by transferring momentum to the flow, which has a destructive effect on the boundary layer. In this study, circular, square and rectangular orifices have been used to investigate numerically the flow and heat transfer for low orifice-to-plate distances by using the FloEFD CFD code. Examinations were carried out for H/d=0.1-1.0, f=250 Hz–500 Hz, td=1.5-5 and R=1.25-1.75 values using single and multiple orifices. Firstly, the effects of H/d and frequency on Nusselt number for circular, square and rectangular orifice geometries were investigated. In general, it was observed that the heat transfer increased when the H/d ratio decreased and the f value increased. In addition, it was observed that the highest heat transfer value was obtained at R=1.75 in multiple orifice arrays. In general, it was seen that the orifice plate thickness has no effect on heat transfer with both local and average Nusselt values. It was observed that the temperature distributions of the four satellite orifice synthetic jet mechanisms are more uniform. It is seen that there is a higher average Nusselt number variation especially at low H/d ratio and high frequencies.

Key Words : Synthetic jet, FloEFD, Heat transfer, CFD