| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 647659 | Applied Thermal Engineering | 2011 | 9 Pages |
This study experimentally and numerically investigates the single-phase flow into parallel flow heat exchangers with inlet and outlet rectangular headers having square cross section and 9 circular tubes. The effects of inlet flow condition, tube diameter, header size, area ratio, flow directions (Z and U-type), as well as the gravity are investigated. The experimental results indicate that flow distribution for U-type flow is more uniform than Z-type flow. Depending on the inlet volumetric flow rate, the flow ratio at the first several tubes can be lower than 50% of the last tube for Z-type arrangement, and this phenomenon becomes more and more pronounced with the rising velocity at the intake conduit. The mal-distribution can be eased via reducing the branching tube size or increasing the entrance settling distance at the intake conduit. It is found that the influence of gravity on mal-distribution is negligible and the mal-distribution is associated with the jet flow pattern.
► The flow distribution into parallel flow heat exchangers with rectangular headers is examined. ► The first several tubes may show only 50% flow rate of the last tube. ► The mal-distribution becomes more severe with the rising velocity at the intake conduit. ► The mal-distribution is mainly associated with the jet flow pattern. ► Flow distribution is improved via smaller tubes or increasing the inlet distance at the intake conduit.
