Minimization of noise of the precision cooling system in the dynamic mode of the electronic apparatus

Abstract

The design of a floor-standing telecommunication cabinet is considered. Air movement inside the cabinet is carried out in the vertical direction due to the simultaneous operation of supply and exhaust ventilation units. The reasons for the increased noise in the dynamic mode of operation are analyzed. The cabinet design is regarded as a mechanical and acoustic resonator with a heat-sensitive element that requires precision cooling. Constant airflow ensures constant element temperature. When the thermal power changes in a dynamic mode of operation, a change in the performance of ventilation units is required. This explains the occurrence of various resonances in the structure and, as a result, increased noise. Airflow consistency can be achieved using alternative operating modes of the supply and exhaust ventilation units. Analytically, families of isothermal supply voltage curves of ventilation units for laminar air movement have been constructed. The noise level's mathematical dependence on the fans' supply voltage is compiled, considering the resonances in the cabinet structure. Noise characteristics corresponding to isothermal voltage curves have characteristic minima. The transition between the isothermal supply voltage curves along the minimum noise trajectory controls the ventilation units. This method's possibility of minimizing noise has been confirmed analytically and experimentally. Keywords: electronic device, heat-sensitive element, ventilation unit, air flow, dynamic mode, isothermal stress curve, resonance, minimization, trajectory, noise.