To solve the existing problems of imperfect sealing and the inaccurate measurement of gas pressure in traditional sealing,the present study builds a new model of capsule-slime sealing device based on wireless pressure...To solve the existing problems of imperfect sealing and the inaccurate measurement of gas pressure in traditional sealing,the present study builds a new model of capsule-slime sealing device based on wireless pressure gauge.The new sealing device is mainly composed of two sets of capsules,a capsule connecting piece and a slime part,measures the pressure through the wireless communication technology,and seals through chemical reaction in the capsule,which generates gas to expand the capsule and extrude the pre-stored slime.Two methods of extruding pre-stored slime are proposed:in the first method,transverse force is generated by the expansion of the capsules at both ends,pushing the capsules toward the middle through the chute and squeezing the pre-stored slime out;in the second,high-pressure gas generated in the capsules is led into the expansion tube,which is inserted into the storage tube,squeezing it and letting the slime out to complete the sealing process.Then the research studies the effect of sealing under the condition of drilling with the structure of slime storage tube.The results indicate that the maximum standing time of slime wrapped in metal net is 2 h,instead of the expected 10 d,failing to meet the sealing requirements.When the slime viscosity is 1200–3000 m Paás in the structure of slime storage tube,the best viscosity of slime is achieved and can simulate sealing the drilling hole(5–4,4–2.36,2.36–1.18,1.18–0.15 mm in diameter),as well as the gap caused by mixed sand accumulation.展开更多
This paper proposes a new-designed rim seal configuration with sealing holes based on the conventional radial rim seal,and presents a numerical comparison of the sealing performance between the conventional sealing fl...This paper proposes a new-designed rim seal configuration with sealing holes based on the conventional radial rim seal,and presents a numerical comparison of the sealing performance between the conventional sealing flow supply configuration and the new sealing flow supply configuration with holes at different sealing flow rates.The sealing effectiveness and unsteady flow yields at the rim seal are numerically simulated by using the URANS method and SST turbulent model from ANSYS CFX.The influence of the new sealing flow supply configuration on the sealing effectiveness at different sealing flow rates is determined.The effectiveness of different sealing flow rates in the conventional rim seal is also studied.As to the conventional rim seal,the increase in the sealing flow rate reduces the degree of gas ingestion induced by the effect of mainstream ingress at the rim clearance,while the unsteady flow characteristics are enhanced,and the number and amplitude of the low-frequency signals increase.The position of the Kelvin-Helmholtz instabilities vortex structures is left by the increased sealing flow rate,and its strength is suppressed.Compared with the conventional rim seal configuration,the new sealing flow supply configuration with holes could reduce the sealing efficiency by 5.06%at most at sealing flow distribution m_(1):m_(2)=3:1 when Cw=2000,and improve the sealing efficiency by 11.71%at most at sealing flow distribution m_(1):m_(2)=1:1 when Cw=7500.It shows that the lateral jet from the holes induces a larger-scale Kelvin-Helmholtz vortex structure at Cw=2000,thus the sealing efficiency in the wheel space is also reduced.However,the size of the Kelvin-Helmholtz vortex structures is significantly suppressed by the new sealing flow supply configuration at Cw=7500,which is beneficial to improving the sealing effectiveness of the conventional rim seal.展开更多
基金the support from the National Key Research and Development Program of China (No. 2017YFC0805201)the Fundamental Research Funds for the Central Universities of China (No. 2017CXNL02)+1 种基金the program for Innovative Research Team in University of Ministry of Education of China (No. IRT13098)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China (PAPD)
文摘To solve the existing problems of imperfect sealing and the inaccurate measurement of gas pressure in traditional sealing,the present study builds a new model of capsule-slime sealing device based on wireless pressure gauge.The new sealing device is mainly composed of two sets of capsules,a capsule connecting piece and a slime part,measures the pressure through the wireless communication technology,and seals through chemical reaction in the capsule,which generates gas to expand the capsule and extrude the pre-stored slime.Two methods of extruding pre-stored slime are proposed:in the first method,transverse force is generated by the expansion of the capsules at both ends,pushing the capsules toward the middle through the chute and squeezing the pre-stored slime out;in the second,high-pressure gas generated in the capsules is led into the expansion tube,which is inserted into the storage tube,squeezing it and letting the slime out to complete the sealing process.Then the research studies the effect of sealing under the condition of drilling with the structure of slime storage tube.The results indicate that the maximum standing time of slime wrapped in metal net is 2 h,instead of the expected 10 d,failing to meet the sealing requirements.When the slime viscosity is 1200–3000 m Paás in the structure of slime storage tube,the best viscosity of slime is achieved and can simulate sealing the drilling hole(5–4,4–2.36,2.36–1.18,1.18–0.15 mm in diameter),as well as the gap caused by mixed sand accumulation.
基金supported by the Special Scientific Research Project of the Ministry of Industry and Information Technology(MJ-2018-D-21)the National Science and Technology Major Project(J2019-III-0003-0046)。
文摘This paper proposes a new-designed rim seal configuration with sealing holes based on the conventional radial rim seal,and presents a numerical comparison of the sealing performance between the conventional sealing flow supply configuration and the new sealing flow supply configuration with holes at different sealing flow rates.The sealing effectiveness and unsteady flow yields at the rim seal are numerically simulated by using the URANS method and SST turbulent model from ANSYS CFX.The influence of the new sealing flow supply configuration on the sealing effectiveness at different sealing flow rates is determined.The effectiveness of different sealing flow rates in the conventional rim seal is also studied.As to the conventional rim seal,the increase in the sealing flow rate reduces the degree of gas ingestion induced by the effect of mainstream ingress at the rim clearance,while the unsteady flow characteristics are enhanced,and the number and amplitude of the low-frequency signals increase.The position of the Kelvin-Helmholtz instabilities vortex structures is left by the increased sealing flow rate,and its strength is suppressed.Compared with the conventional rim seal configuration,the new sealing flow supply configuration with holes could reduce the sealing efficiency by 5.06%at most at sealing flow distribution m_(1):m_(2)=3:1 when Cw=2000,and improve the sealing efficiency by 11.71%at most at sealing flow distribution m_(1):m_(2)=1:1 when Cw=7500.It shows that the lateral jet from the holes induces a larger-scale Kelvin-Helmholtz vortex structure at Cw=2000,thus the sealing efficiency in the wheel space is also reduced.However,the size of the Kelvin-Helmholtz vortex structures is significantly suppressed by the new sealing flow supply configuration at Cw=7500,which is beneficial to improving the sealing effectiveness of the conventional rim seal.
