Measurement and Visualization of R134a Distribution in the Vertical Header of the Microchannel Heat Exchanger Univ of Illinois at Urbana-Champaign

Format:

Conference/Event

Author/Creator:

Zou, Zou, author.

Contributor:

Hrnjak, Predrag

Conference Name:

SAE 2013 World Congress & Exhibition (2013-04-16 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2013

Summary:

Distribution of R134a in four different vertical headers of microchannel heat exchanger was investigated experimentally. R134a was provided into the header by the microchannel tubes (5 or 10 tubes) in the bottom pass. It left the header through the microchannel tubes (5 or 10 tubes) in the top pass representing the upward flow in the heat pump mode of the reversible systems. The inlet quality was varied from 0.2 to 0.8, and the inlet mass flow rate was from 1.5 to 4.5 kg/h per microchannel tube. Among the test conditions, the aluminum and transparent headers show similar results: refrigerant distribution is better when reducing quality at the same mass flow rate and when increasing mass flow rate at the same quality. Increasing the tubes protrusion and the number of the microchannel tubes usually improve the distribution due to the increase in mass flux. Based on the visualization, churn and separated flow regimes are identified. The churn flow usually has better distribution than the separated flow since the two-phase mixture is more homogeneous. The distribution is better at high mass flux in the header because the higher momentum liquid can be supplied to the top exit tubes

Notes:

Vendor supplied data

Publisher Number:

2013-01-1498

Access Restriction:

Restricted for use by site license