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Noise Cancellation Mechanism/Configuration for Synthetic Jets

IP.com Disclosure Number: IPCOM000029138D
Publication Date: 2004-Jun-16
Document File: 2 page(s) / 31K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for reducing the noise generated by the synthetic jets used to cool small electronic devices.

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Noise Cancellation Mechanism/Configuration for Synthetic Jets

Disclosed is a method for reducing the noise generated by the synthetic jets used to cool small electronic devices.

Background

Synthetic jets cool small electronic devices by using of an oscillating diaphragm (or other elastic membrane) in a chamber. The oscillation is generated by connecting the diaphragm to a sinusoidal or other periodic waveform. When the diaphragm compresses the fluid in the chamber, the fluid leaves through an orifice at a relatively high velocity, resulting in a higher mass flow rate of air. During the expansion of the air, the outside air is drawn into the chamber.  This process is repeated at medium to high frequencies, depending on the desired flow characteristics. Since the air changes intensity and direction in the flow chamber, the resulting heat transfer coefficient is enhanced as compared to a configuration that generates a constant flow (e.g. a fan). However, an inherent drawback of this technique is that the elastic element must be modulated at a particular frequency. This oscillation is highly concentrated, and manifests itself as a buzzing or humming sound.

General Description

The disclosed method reduces the noise generated by the synthetic jets used to cool small electronic devices. The disclosed method uses multiple synthetic jets driven at frequencies that may or may not be the same. The frequency and phases of the oscillations are such that the noise generated by one diaphr...