A series of vortex tube nozzles were designed and fabricated,and the effect of various cross sections of nozzle and the number of the nozzle intakes on the energy separation performance of a vortex tube were investiga...A series of vortex tube nozzles were designed and fabricated,and the effect of various cross sections of nozzle and the number of the nozzle intakes on the energy separation performance of a vortex tube were investigated experimentally by using air as test fluid. The experimental results showed that the vortex tube with the nozzle cross section designed in this study was superior to that with the nozzles of normal rectangle cross section and that of Archimedes’ spiral type in terms of regeneration temperature performance under the condition of ambient temperature with inlet pressure of 0.4 MPa.The cooling performance of the vortex tube with four intakes nozzle was the best while that of the vortex tube with eight intakes nozzle was the worst under the same experimental condition.展开更多
为有效控制喷口区域气流运动、提高高压开关开断能力,以高压SF6断路器(HV SF6 CB)为研究对象,在喷口上游平直段构造"X"形导流片结构,使气流形成涡旋运动产生能量分离,气流产生径向动能交换以调控断口区域气流温度梯度。建立55...为有效控制喷口区域气流运动、提高高压开关开断能力,以高压SF6断路器(HV SF6 CB)为研究对象,在喷口上游平直段构造"X"形导流片结构,使气流形成涡旋运动产生能量分离,气流产生径向动能交换以调控断口区域气流温度梯度。建立550 k V SF6断路器灭弧系统3维气流场物理数学模型,采用有限体积法研究容性小电流开断下,喷口上游"X"型导流片对灭弧室内气流参数的影响。结果表明,有导流片结构灭弧室断口区域内的气流呈组合涡运动形式,沿壁面周向呈大旋转曲率强旋运动,轴中心气流折返,断口区域温度降低,产生了能量分离效应。展开更多
提出新型能量分离型喷口结构,在喷口上游引入X型导流片,以改变气流流路。为分析新型喷口对灭弧室内部电场分布的影响,采用有限元法,结合550 k V SF6断路器绝缘型式实验要求,对有无导流片结构的高压SF6断路器灭弧系统的绝缘特性进行数值...提出新型能量分离型喷口结构,在喷口上游引入X型导流片,以改变气流流路。为分析新型喷口对灭弧室内部电场分布的影响,采用有限元法,结合550 k V SF6断路器绝缘型式实验要求,对有无导流片结构的高压SF6断路器灭弧系统的绝缘特性进行数值计算与分析,得到在开断过程中导流片结构对断路器灭弧室内电场分布的影响。三维电场计算结果表明,有导流片结构的灭弧室内部最大电场强度值较无导流片结构有所降低,最大降低量为4.8%。展开更多
Acquisition of the temperature distributions inside the vortex tube is a principal and key problem for disclosing the fundamental mechanism underlying the energy separation effect inside the tube.The “Realizable κ-...Acquisition of the temperature distributions inside the vortex tube is a principal and key problem for disclosing the fundamental mechanism underlying the energy separation effect inside the tube.The “Realizable κ-ε” turbulence model of computational fluid dynamics (CFD) was used to simulate the energy separation effect produced by three-dimensional compressible flow with strong swirl inside the vortex tube.Then the axial and radial distributions of total and static temperature were obtained.The mean kinetic energies and the stagnation enthalpies of the peripheral and inner flows per unit mass along the airflow direction were also examined respectively because the enveloping surface of zero axial velocity is the interface between peripheral and inner airflows.In order to validate the numerical results, comparisons between the numerical predictions and the experimental results were conducted for the cold air temperature drops as a function of cold fraction, and satisfactory agreements were observed.A non-dimensional strategy was adopted to compare total, static temperature distributions along the radial direction at a given axial location with the experimental data from previous studies, so the accuracy of the numerical results was further validated.展开更多
文摘A series of vortex tube nozzles were designed and fabricated,and the effect of various cross sections of nozzle and the number of the nozzle intakes on the energy separation performance of a vortex tube were investigated experimentally by using air as test fluid. The experimental results showed that the vortex tube with the nozzle cross section designed in this study was superior to that with the nozzles of normal rectangle cross section and that of Archimedes’ spiral type in terms of regeneration temperature performance under the condition of ambient temperature with inlet pressure of 0.4 MPa.The cooling performance of the vortex tube with four intakes nozzle was the best while that of the vortex tube with eight intakes nozzle was the worst under the same experimental condition.
文摘为有效控制喷口区域气流运动、提高高压开关开断能力,以高压SF6断路器(HV SF6 CB)为研究对象,在喷口上游平直段构造"X"形导流片结构,使气流形成涡旋运动产生能量分离,气流产生径向动能交换以调控断口区域气流温度梯度。建立550 k V SF6断路器灭弧系统3维气流场物理数学模型,采用有限体积法研究容性小电流开断下,喷口上游"X"型导流片对灭弧室内气流参数的影响。结果表明,有导流片结构灭弧室断口区域内的气流呈组合涡运动形式,沿壁面周向呈大旋转曲率强旋运动,轴中心气流折返,断口区域温度降低,产生了能量分离效应。
文摘提出新型能量分离型喷口结构,在喷口上游引入X型导流片,以改变气流流路。为分析新型喷口对灭弧室内部电场分布的影响,采用有限元法,结合550 k V SF6断路器绝缘型式实验要求,对有无导流片结构的高压SF6断路器灭弧系统的绝缘特性进行数值计算与分析,得到在开断过程中导流片结构对断路器灭弧室内电场分布的影响。三维电场计算结果表明,有导流片结构的灭弧室内部最大电场强度值较无导流片结构有所降低,最大降低量为4.8%。
文摘Acquisition of the temperature distributions inside the vortex tube is a principal and key problem for disclosing the fundamental mechanism underlying the energy separation effect inside the tube.The “Realizable κ-ε” turbulence model of computational fluid dynamics (CFD) was used to simulate the energy separation effect produced by three-dimensional compressible flow with strong swirl inside the vortex tube.Then the axial and radial distributions of total and static temperature were obtained.The mean kinetic energies and the stagnation enthalpies of the peripheral and inner flows per unit mass along the airflow direction were also examined respectively because the enveloping surface of zero axial velocity is the interface between peripheral and inner airflows.In order to validate the numerical results, comparisons between the numerical predictions and the experimental results were conducted for the cold air temperature drops as a function of cold fraction, and satisfactory agreements were observed.A non-dimensional strategy was adopted to compare total, static temperature distributions along the radial direction at a given axial location with the experimental data from previous studies, so the accuracy of the numerical results was further validated.
