OPTIMIZATION OF LOCAL HEAT TRANSFER IN AN IMPACT JET USING ACTIVE FLOW CONTROL AND FEEDBACK
M. P. Tokarev, M. Yu. Nichik, O. A. Gobyzov, I. A. Fedotov, V. M. Dulin
Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: heat transfer, turbulent impact jet, flow rate disturbances, forced oscillations, self-oscillation, feedback, machine learning
Abstract
The development of methods for controlling the flow and heat transfer in submerged turbulent jets (impact jets) impinging on an obstacle is an important task, because such a configuration is used in various technical applications. The active flow control technology and optimization of the signal that controls the external flow disturbance in impact jets can be applied to exploit the inherent properties of the flow to further enhance heat transfer at the wall. IR thermography is used and measurements are carried out using the PIV (Particle Image Velocimetry) method for optical diagnostics of the wall temperature fields and velocity fields under conditions of flow disturbance control, including feedback from a local velocity sensor. It is found that low-amplitude sinusoidal disturbances increase the integral temperature at the wall due to the intensification of flow separation at the wall compared to an undisturbed jet. It is also established that high-amplitude disturbances in the pulsating jet mode make it possible to reduce the integral temperature by increasing the average flow velocity near the wall and compensate for the undesirable effect of flow separation. The genetic programming algorithm makes it possible to find a self-oscillating regime during jet disturbance with feedback, which improves local heat transfer on the wall not worse than in the case of a forced periodic disturbance.
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