Pressure drop in round cylindrical headers of parallel flow MCHXs: Pressure loss coefficients for single phase flow

• Pressure drops for single phase flow through round cylindrical header are studied.
• The non-uniformity of pressure loss coefficient in header is investigated.
• Correlations for pressure loss coefficients for single phase flow are proposed.

This paper presents the investigation of the pressure drop in headers and development of correlation for pressure loss coefficient for single phase flow through round cylindrical headers of parallel MCHXs. The working fluid was compressed air flowing through header with 1–20 m s−1 based on smallest cross section while the velocity through microchannels was in the range 6–30 m s−1. The experimental results indicate that the pressure loss coefficient of inlet header is a linear function of the ratio of velocities through microchannel tube and header, except for the first two microchannel tubes; the pressure loss coefficient of outlet header is a quadratic function of the ratio of velocities through microchannel tube and header, and decreases as the velocities through upstream microchannel tubes increase. Correlations for predicting pressure drop of inlet header and outlet header are developed and agreement for 98% of experimental data is within a ±15 Pa.