Summary

The efficiency of reciprocating compressors adopted for household refrigeration is directly affected by the refrigerant superheating along the suction muffler. This dissertation reports an experimental investigation of heat transfer in the suction muffler of a variable-speed compressor. The study analyzes the effects of compressor speed (1200, 2000 and 4000rpm) and pressure ratio, given by the evaporating/condensing temperatures of (15.0°C/40.0°C) and (-25.0°C/40.0°C), on the heat transfer. Thermocouples and heat flux sensors allowed measurements of temperature and heat flux for different operating conditions. The results showed that heat transfer in the suction muffler is strongly affected by the evaporating pressure and compressor speed. Based on the measurements, heat transfer correlations are proposed and compared with correlations available in the literature. Correlations developed for spheres provided results in good agreement with experimental data for the external surface. On the other hand, the correlation of Dittus-Boelter and Gnielinski provided satisfactory agreement with measurements for the flow through tubes, but the same not happening inside the volumes of the suction filter.

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