English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Steady and unsteady pressure losses in sudden expansion and sudden contraction in pneumatic piping systems are studied. An experimental study for steady state loss coeffi cients was carried out with pipes having expansion ratios (=pipe diameter ratio) of 1.2, 1.5 and 2.0, and contraction ratios of 5/6, 2/3 and 1/2. The Reynolds number downstream of the sudden cross section changes lies between about 5,000 and 36,000. The diff erence between the obtained loss coeffi cient and commonly known data that were obtained with water is about 10% . After steady-state measurement, pressure losses due to the cross-section changes in pulsatile fl ow are estimated and compared with the experiments. The estimate was made ignoring the compressibility of the fl uid, and assuming the same value of loss coeffi cient as in the steady fl ow. The experiments were carried out using the same expansion and contraction pipes used in the steady-state experiment. The frequency of the pulsation is 1~30 [Hz]. The mean Reynolds numbers of the pulsatile fl ows were 12,000~ 26,000 and the amplitude Reynolds numbers were about 27% of the corresponding mean Reynolds numbers. Diff erences between the estimates and the experiments are within 3% with contraction pipes, up to 15% with expansion pipes.

Estimate of Pressure Losses in Steady and Pulsatile Flows through Sudden Expansion and Contraction of Pipes