Dewetting of a water film between a solid and a viscoelastic liquid

Abstract Water lubricated guide bearings for hydro turbines and pumps are conventionally designed with multiple axial grooves to provide effectively cooling and flushing away abrasives. Due to the variety of groove configuration in terms of number and size, a predication of their performance is difficult. This paper deals with an analytical procedure to investigate groove effect on load capacity, stiffness and damping for this type of bearing where it is considered as an assembly of many inclined slide bearings. The result can be applied to bearings made of hard materials combined with low bearing pressure.

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Oscillation of satellite droplets in an Oldroyd-B viscoelastic liquid jet

Physical Review Fluids ◽

10.1103/physrevfluids.2.013602 ◽

2017 ◽

Vol 2 (1) ◽

Cited By ~ 1

Author(s):

Fang Li ◽

Xie-Yuan Yin ◽

Xie-Zhen Yin

Keyword(s):

Viscoelastic Liquid ◽

Liquid Jet

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Evaluation on the performance fluctuation after water ingestion for a turbofan engine compressor during flight descent

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020977982 ◽

2020 ◽

pp. 095441002097798

Author(s):

Lu Yang ◽

Qun Zheng ◽

Aqiang Lin

Keyword(s):

Droplet Diameter ◽

Pressure Ratio ◽

Critical Role ◽

Water Film ◽

Heavy Rain ◽

Diameter Distribution ◽

Turbofan Engine ◽

Water Ingestion ◽

The Core ◽

Engine Compressor

Turbofan engine compressor is most severely threatened by the entry of liquid water during flight descent. This study aims to deeply understand the fluctuations of compressor performance parameters caused by water ingestion through frequency spectrum analysis. The water content and droplet diameter distribution are determined based on the real heavy rain environment. Results reveal that most of the droplets actually entering the core compressor have a particle size of less than 100 μm. In addition, the formation and motion of water film plays a critical role in affecting the fluctuation characteristics. Water ingestion deteriorates the compression performance and aggravates the unsteady fluctuations of the fan. However, the performance of the core compressor is less affected by water ingestion, but their fluctuations are still exacerbated. For some important parameters, such as inlet mass flow rate, total pressure ratio, total temperature ratio, compression work and efficiency, their main frequency of fluctuation are switched from the original blade passing frequency to the rotor passing frequency, and their amplitudes are correspondingly amplified to varying degrees. These phenomena can be observed in both the fluctuations of the fan and core compressor. Moreover, the operating point of them will be in the long-period and large-amplitude fluctuations, which leads them experiences the non-optimal state for a long time and threatens their operating stability.

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