NOISE REDUCTION TECHNOLOGY WITH POROUS METAL FOR REFRIGERANT TWO-PHASE FLOW THROUGH THE EXPANSION VALVE

Abstract

Refrigerant gas-liquid two- phase flow through the expansion valve makes noise. This report introduces new noise reduction technology with porous metal for refrigerant two-phase flow. We visualized the test section of the orifice using as the expansion valve and measured noise level in the orifice with or without porous metal. The noise level of the split type room air-conditioner was measured installing the orifice into the indoor unit. The testing results show that porous metal of upstream of the orifice mixes vapor and liquid and that of downstream of it reduces pressure fluctuation of two-phase flow, therefore noise reduction is achieved.