Application And Fluid Control Mechanism Of Morphology/Materials Bionic Coupling Functional Surface (BCFS)

Studies have shown that the structure of dolphin skin controls fluid mediadynamically and achieves drag reduction function. Gaining inspiration from thisphenomenon, a kind of Morphology/Materials Bionic Coupling Functional Surface(BCFS) was designed. The BCFS is composed of two materials: a rigid metal baselayer with bionic structures and an elastic polymer surface layer with correspondingmirror structures. The BCFS was applied to the impeller of a centrifugal pump in acontrast experiment.Design and manufacture the special mold of bionic form by five-axis machiningcenter on the basis of secondary stamping processing technology. According to thepreliminary optimized size and the layout location, we use the five-axis machiningcenter to machine the bionic form on Aluminum alloy surface. Then we manufacturedbionic mold with the method of secondary stamping according to the actual curvatureof the centrifugal pump impeller. In order to ensure the accuracy of bionic form anddimension and prevent the deformation of aluminum alloy in the process ofmachining, the processing size should be smaller than design size.Through a largenumber of experiments, we find that processing size should be smaller than designsize0.5mm or so. Comparing with once casting molding process the sand mold madeby the mold of bionic form has continuous bionic form、high quality、high efficiencyand is less influenced by external factors. That provided a technical foundation for thewidely used of this kind of bionic coupling surface in engineering. Mass production ofbionic coupling pumps was carried out based on the bionic form special mould. Then,test the bionic coupling pumps of the batch production to verify the efficiency isimproved.The fluid control mechanism of the BCFS was investigated using a fluid-solid interaction (FSI) method in ANSYS-Workbench. The key factor in the BCFS’s fluidcontrol mechanism is its elastic deformation, which is caused by the coupling actionbetween the elastic surface material and the bionic structure of the basal material. Thisdeformation decreases the velocity gradient of the fluid boundary layer and resultingin frictional force reduction. The BCFS can also absorb some energy through elasticdeformation, effectively reducing the turbulent kinetic energy and avoiding excessiveexchange of the fluid-solid interface and energy loss, so as to achieve the effect ofdrag reduction.