Laboratory testing of flat oval transitions to determine loss coefficients (RP-1606)

Yigang Sun, Steven E. Ford, Yuanhui Zhang

Research output: Contribution to journalArticlepeer-review


Pressure loss coefficientsweremeasured for 8 converging-concentric, 15 converging-eccentric, 8 diverging-concentric, and 15 divergingeccentric flat oval transition fittings. All tests were performed in accordance with ASHRAE Standard 120-2008, Method of Testing to Determine Flow Resistance of HVAC Ducts and Fittings, except (1) the entrance duct length to the test fitting was increased to 12 hydraulic diameters and (2) the fitting loss coefficient was calculated as the slope of the linear regression of pv8 (downstream velocity pressure) versus Δpt,1-2 (zero-length total pressure loss of a test fitting) instead of pv7 (upstream velocity pressure) versus Δpt,1-2. An Excel template file was developed to perform experimental data processing, graphical expression, and uncertainty analysis. Two pressure loss coefficient equations were developed, one for converging and a second for diverging fittings based on the experimental data. The loss coefficient regression equations will be added to the ASHRAE Duct Fitting Database, thus increasing the population of flat oval fittings.

Original languageEnglish (US)
Pages (from-to)386-395
Number of pages10
JournalScience and Technology for the Built Environment
Issue number4
StatePublished - 2015

ASJC Scopus subject areas

  • Environmental Engineering
  • Building and Construction
  • Fluid Flow and Transfer Processes


Dive into the research topics of 'Laboratory testing of flat oval transitions to determine loss coefficients (RP-1606)'. Together they form a unique fingerprint.

Cite this