| In blood pump research process, the researchers are stranded continuously by the question of lubrication and the seal between the mechanical movement parts. Using the human blood as the friction lubricant between the movement parts is an effective way to solve the difficult problem. Because the blood is a kind of special material which has the life characteristics, people before mainly concentrates the research on the blood in the medicine domain, there are very few researchers to study the blood friction lubricity specially. Aiming to physiological characteristics, hemorheologic characteristics and physics and chemistry characteristics of blood, using hemorheology theory and hydrodynamic lubrication theory, this article discussed the blood lubricity and studied the lubricity of blood self-lubricating journal bearing in the minimal axial blood pump driven by extra magnetic field. From the blood applications in engineering, this paper attempts to study the blood lubricity, and provides the basis for blood pump to use human blood as lubricant directly. The main contents include:(1) Analyzed normal human blood component and the hemorheologic characteristics, studied the blood component changing in the lubrication area with the simplified rigid-brittle cell model, and analyzed influence of the lubricant film thickness on lubricant film component. Considering deformability of the blood cell, tested the ability of blood cell through different gap under different shear rate. The result showed that different smallest gap and shear rate are main factors to affect the HCT in the blood lubrication entrance region and the outlet area. Otherwise, the experiment on relations between HCT and the blood apparent viscosity is performed, and micro mechanism of non-stablility lubrication of blood is analyzed.(2) With the low osmotic pressure hemolysis model and shear flow hemolysis model, proposed that the negative pressure and shear flow are key factors for hemolysis. Using four-ball friction apparatus, studied the blood mechanical loading capacity and hematolysis under different rotational speed, and proposed synthesis determination of blood loading capacity considering physiologic and mechanical requirement.(3) The loading capacity is a important factor for blood lubrication. Aiming to the engineering application of blood, analyzed the influences of hemorheologic characteristics, dynamic pressure effect, physics and chemistry response of blood ingredient under high temperature, viscosity-temp characteristics and viscosity-pressure characteristics of blood on mechanical loading capacity of blood. Under multi factors coupling, studied the changing regulations of mechanical loading capacity of blood, and analyzed main factors in different lubricating condition.(4) The blood hemorheologic indexes influence the friction and lubricity of blood. Tested the changing regulations of hemorheologic indexes of human blood of different sexes and different ages aiming at the crowd (male:300,female:300) of ChangSha region. Proposed that different reference standard value of blood hemorheologic indexes must be used for different crowed in blood self-lubricating pump designing and the medicine examination.(5) According to the dynamic distribution of magnetic field in magnetic coupling transmission of blood pump driven by extra magnetic field, analyzed changing rules of the radial force and torque during the transmission by means of analytic calculation with the concept of magnetic core, and established the calculation model of the radial magnetic coupling force and torque. Using hydrodynamic lubrication theory, established the blood lubrication model of stability loading journal bearing under high shear rate for different lubricant film thickness. Taking blood self-lubricating blood pump driven by extra magnetic field as an example, calculated pressure distribution, loading capacity, friction force and friction power loss in blood lubrication area, and analyzed the relations between radius difference, rotational speed and blood loading capacity. The principles for designing journal bearing of blood self-lubricating blood pump are proposed.
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