Lu Longsheng

Flow Distribution among Microchannels with Asymmetrical Manifolds

A microchannel physical model is developed to study the flow distribution among microchannels, and the flow rate in each microchannel is worked out by a numerical analysis method. A specific case is illustrated to study the influence of asymmetrical manifolds on the flow distribution among microchannels, and the results are compared with the microchannels with symmetrical manifolds. Results indicate that the flow distributions among microchannels with symmetrical manifolds are much more uniform than that with asymmetrical ones. The rake angles have a considerable effect on the flow distribution among microchannels with asymmetrical manifolds and the short vertical sides show a slight influence.

Influences of Sedimentation Time and Target Current Ratio on Wear Resistance of a Magnetron Sputtered TiAlN Coating

Abstract A TiAlN coating on the surface of a WC-8Co cemented carbide matrix with thicknesses ranging from 2.5μm to 3.5 μm and different ratios of Ti/Al was synthesized by magnetron sputtering. The carrying capacity and tribological performance of the coating were investigated on a friction-wear testing machine; the microstructure of the coating was observed by scanning electron microscopy. The tribological performance of TiAlN coatings with different compositions and thicknesses was evaluated through the friction coefficient and the evolution of microstructure. The results show that when the coating thickness increases, the friction coefficient decreases, and the coating will not easily wear out, suggesting that it is beneficial to improve the wear resistance of a coating by increasing its thickness in a certain range. If the composition of the coating changes, its friction performance will vary due to the different effects of Ti and Al. when the Ti/Al ratio is 50:50, the wear resistance of the coating is best