The rapid development of Industrial science and technology has higher requirements for the high-level practicality of mechanical seals. While meeting the sealing requirements, how to improve the throttling efficiency, reduce the maintenance cycle, improve the seal life and structural stability is of great significance for the practical application of sealing technology. At present, the traditional mechanical seal mainly relies on the direct solid contact (contact type) of the seal ring or the introduction of blocking fluid (non-contact type) to block the leakage channel. The former is efficient and reliable, simple structure but high power consumption and short service life, while the latter has low power consumption and long service life but complex structure and low throttling efficiency. In particular, the technology of non-contact sealing products for high-end equipment such as gas turbines and engines is complex and systematic. Based on the existing sealing structure, it is difficult to achieve theoretical innovation and technological breakthrough of high-performance sealing products. Therefore, it is urgent to make original breakthroughs in the existing seal forms and theories, and innovate a new technology and structure of non-contact mechanical seal with high efficiency, zero wear, simple structure and outstanding stability. Tesla valve has been successfully applied in various fluid flow control fields with its unique structure and one-way conduction characteristics. Its ingenious step-by-step impact blocking characteristics in reverse flow have high throttling efficiency. This project was based on the passive fluid control principle and impact blocking throttling method of the planar Tesla valve structure, and according to the unique one-way conduction characteristics of this structure, it was proposed to expand this ingenious structure fromed planar flow to three-dimensional channel flow, upgraded the one-way conduction characteristics for sealing one-way (high pressure side to low pressure side) leakage suppression under non-contact operation, realized the unique macro three-dimensional reconstruction of the micro leakage channel of the traditional seal, and built a new sealing function and structure with non-contact, zero wear, low leakage and simple structure. Through the systematic simulation calculation of different working conditions and geometric parameters, the performance characteristics and optimal parameter range of the new seal was obtained.
The results showed that the medium pressure P, seal spacing h and seal series Z significantly affected the performance of the new seal, the predetermined sealing performance could be achieved by reducing the seal spacing and increasing the seal series. The new seal was more suitable for high-density and high-viscosity medium. The optimal interval of the shunt angle of the 3D flow channel of the sealing was the same as that of the planar Tesla valve. The sealing performance was not sensitive to speed changes, and it was also suitable for low speed or even shutdown. Taking the standard leakage as the index, the corresponding critical seal spacing of the new seal series Z = 4, 8 and 12 was h = 24, 26 and 30 μm, respectively, which was more than ten times or even dozens of times that of the dry gas seal under the same working conditions, and the new seal spacing was rigid clearance for higher stability. Based on the proposal of a new type of seal in this paper, it was expected to develop a new technology of fluid seal, and formed a technological innovation in the existing sealing field.
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