NCEPU wave-finned flat tube: the air-side fit against its own wind tunnel
Tier 2: measurement on a controlled rig.
- What was compared
- The air-side heat transfer coefficient of the NCEPU wave-finned flat tube, as given by the polynomial fit the catalogue carries for it, at the ten measured points of a wind tunnel test.
- Against
- Yang et al.'s wind tunnel measurement of the tube (Yang et al., 2012, Fig. 5, the experimental points only, digitised), with stated uncertainties of 7% on the Nusselt number and 4% on the friction factor. The case is Tier 2.
- The agreement
- Four of the ten points, at face velocities of 1.93 to 3.34 m/s, lie within the 7% tolerance. Outside that range the fit reads 18% low at the bottom of the measured range and 30% high at the top.
- What it shows
- The polynomial was fitted to this same measurement (Kong et al.), so the case measures the fit's own parameter error and sets the tube's declared range of face velocity. It does not measure model form.
- Source
- L. Yang, X. Tan, X. Du, Y. Yang, 'Thermal-flow characteristics of the new wave-finned flat tube bundles in air-cooled condensers', International Journal of Thermal Sciences 53 (2012) 166-174Fig. 5, the experimental symbols only. The numerical symbols beside them are the same paper's CFD and are Tier 3.