| With the continuous development of economy and socity,the demand for different hydraulic machinery in industry increases greatly,which makes the hydraulic machinery get unprecedented progress and development.Among them,the rotary lobe pump as a non-contact rotary displacement pump has attracted more and more attention and study becase of the advantages of simple structure,stable performance,low cost.Due to the rapid development of petrochemical industry,the requirements of viscous oil transportation gradually increase,and the defects of centrifugal oil pump gradually appear.The working principle and structural charavteristics of rotary lobe pump have innate advantages in the field of viscous oil conveying.And how to work the characteristics of the rotary lobe pump and in the viscous oil transfer advantages show out has become one of foucus of this paper.With the deepening of research,because of the non-contact of the rotary lobe pump,the birth defect is serious internal leakage.Internal leakage problem exists in all pumps.It is more obvious in the positive displacement pump,because it has a direct effect on the pump performance.The performance of different type profile rotos in the working process and the inhibition effect on internal leakage have obvious differences,so in order to reveal the characteristics of internal of rotary lobe pump and the performance and the principle of internal leakage in different rotor type profiles.It is very necessary to study the internal leakage problem of different type profile rotors.Based on the above,three blades of circular arc,involute and cycloid are taken as the research object to study the characteristics of the profile and the governing equation of the rotor in this paper.At the same time,the cycloid rotor was taken as the research object to study its transport performance under 5 different viscous oils.The results showed that: With the increase of medium viscosity,the flow rate at the outlet increases and the flow inside the pump is more stable.The viscous force in the cavity has obvious effect on the flow and cannot be ignored.Moreover,the viscosity oil has a great difference in response to the rotation speed.When the rotation speed of 0.01Pa·s viscosity medium decreases from 400r/min to 100r/min,the flow r ate decreases by more than 95%,while the flow rate of 0.065Pa·s viscosity medium decreases by about 80%.Then,the performance parameters and internal leakage characteristics of three types of line rotors are analyzed,and the internal leakage characteris tics of different types of line rotors are revealed.The results show that: The simulated flow arc line < the pendulum line < the involute line under the working pressure of 0.4mpa has the volumetric efficiency of 32.1%,80.4% and 69.1% respectively.The velocity in the involute and pendulum linear cavity is generally kept below 4-5m /s,the velocity distribution in the independent chamber is even,and the rotor clearance leakage quantity is less,which makes the wake area and the inlet end velocity stable.In addition,different types of line rotors have great influence on flow velocity,pressure distribution and rotor stress in the clearance.Finally involute rotor as the research object to analyze blades rotor optimization,the effect of blades rotor control equation is deduced,blades rotor is analyzed under water medium and viscous oil medium flow characteristics and performance of the flow and the internal mechanism of rotor blades have a preliminary understanding,laying the groundwork for subsequent optimization work.The results showed that under the condition of 0.4mpa clear water medium,the rotor leakage ratio of different blade types was 23.24% for 3 blades,20.07% for 4 blades,25.11% for 5 blades and 36.65% for 6 blades.The outlet flow rate of viscous oil 0.03Pa·s is about 20% higher than that of clear water medium with 4,5 and 6 leaves.Meanwhile,the stress condition of the cavity rotor can be improved with viscous oil medium. |
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