This paper outlines a plan for the effective reduction of the audible sound level produced by aerodynamic noise from the power-generating turbine blades. The contribution of aerodynamic noise can be divided into two c...This paper outlines a plan for the effective reduction of the audible sound level produced by aerodynamic noise from the power-generating turbine blades. The contribution of aerodynamic noise can be divided into two categories: inflow turbulence and airfoil self-noise. The base model and retrofit blade designs were modeled in SolidWorks. Subsequently, noise prediction simulations were conducted and compared to the base blade model to determine which modification provided the greatest benefit using SolidWorks Flow Simulation. The result of this project is a series of blade retrofit recommendations that produce a more acoustically efficient design and reduce noise complaints while enabling turbines to be placed in locations that require quieter operations.展开更多
This paper provides a new system and concept concerning to MEMS air turbine power generator. The generator was composed of the MEMS air turbine and the magnetic circuit. The magnetic circuit was fabricated by multilay...This paper provides a new system and concept concerning to MEMS air turbine power generator. The generator was composed of the MEMS air turbine and the magnetic circuit. The magnetic circuit was fabricated by multilayer magnetic ceramic technology and achieved monolithic structure which included high permeability material and three di-mensional helical conductor patterns inside. Although the output power was micro watt class, some features were extracted by comparing to the simple winding wire type magnetic circuit. In the power density measurement, almost same output power density was extracted though the turn number of the winding wire type was more than that of monolithic type. Also the resistance of the conductor was quarter of the winding type. The maximum output voltage and the maximum power of the monolithic generator was 6.2 mV and 1.92 μVA respectively. The DC conductor resistance was 1.2 Ω. The energy density was 0.046 μVA/mm3. The appearance size of the monolithic type was 3.6, 3.4, 3.5 mm, length, width and height respectively.展开更多
In this article a new principle of geometric design for blade's surface of an impeller is provided.This is an optimal control problem for the boundary geometric shape of flow and the control variable is the surfac...In this article a new principle of geometric design for blade's surface of an impeller is provided.This is an optimal control problem for the boundary geometric shape of flow and the control variable is the surface of the blade.We give a minimal functional depending on the geometry of the blade's surface and such that the flow's loss achieves minimum.The existence of the solution of the optimal control problem is proved and the Euler-Lagrange equations for the surface of the blade are derived.In addition,under a new curvilinear coordinate system,the flow domain between the two blades becomes a fixed hexahedron,and the surface as a mapping from a bounded domain in R2 into R3,is explicitly appearing in the objective functional.The Navier-Stokes equations,which include the mapping in their coefficients,can be computed by using operator splitting algorithm.Furthermore,derivatives of the solution of Navier-Stokes equations with respect to the mapping satisfy linearized Navier-Stokes equations which can be solved by using operator splitting algorithms too.Hence,a conjugate gradient method can be used to solve the optimal control problem.展开更多
A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stato...A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stator of a high pressure steam turbine. For comparison, we have studied the effects of bowed blades on the wakes of stator trailing edge and horse shoe vortex in the rotor. It was found that the position of wakes for bowed blades is shifted toward the blade suction side. Also, we have discussed and compared the entropy generation and energy loss caused by dissipation mechanism within the boundary layers on the hub and shroud; and temperature gradient in meridional plane.展开更多
文摘This paper outlines a plan for the effective reduction of the audible sound level produced by aerodynamic noise from the power-generating turbine blades. The contribution of aerodynamic noise can be divided into two categories: inflow turbulence and airfoil self-noise. The base model and retrofit blade designs were modeled in SolidWorks. Subsequently, noise prediction simulations were conducted and compared to the base blade model to determine which modification provided the greatest benefit using SolidWorks Flow Simulation. The result of this project is a series of blade retrofit recommendations that produce a more acoustically efficient design and reduce noise complaints while enabling turbines to be placed in locations that require quieter operations.
文摘This paper provides a new system and concept concerning to MEMS air turbine power generator. The generator was composed of the MEMS air turbine and the magnetic circuit. The magnetic circuit was fabricated by multilayer magnetic ceramic technology and achieved monolithic structure which included high permeability material and three di-mensional helical conductor patterns inside. Although the output power was micro watt class, some features were extracted by comparing to the simple winding wire type magnetic circuit. In the power density measurement, almost same output power density was extracted though the turn number of the winding wire type was more than that of monolithic type. Also the resistance of the conductor was quarter of the winding type. The maximum output voltage and the maximum power of the monolithic generator was 6.2 mV and 1.92 μVA respectively. The DC conductor resistance was 1.2 Ω. The energy density was 0.046 μVA/mm3. The appearance size of the monolithic type was 3.6, 3.4, 3.5 mm, length, width and height respectively.
基金This work was supported bythe National Natural Science Foundation of China(No.50306019,40375010,10471110,10471109).
文摘In this article a new principle of geometric design for blade's surface of an impeller is provided.This is an optimal control problem for the boundary geometric shape of flow and the control variable is the surface of the blade.We give a minimal functional depending on the geometry of the blade's surface and such that the flow's loss achieves minimum.The existence of the solution of the optimal control problem is proved and the Euler-Lagrange equations for the surface of the blade are derived.In addition,under a new curvilinear coordinate system,the flow domain between the two blades becomes a fixed hexahedron,and the surface as a mapping from a bounded domain in R2 into R3,is explicitly appearing in the objective functional.The Navier-Stokes equations,which include the mapping in their coefficients,can be computed by using operator splitting algorithm.Furthermore,derivatives of the solution of Navier-Stokes equations with respect to the mapping satisfy linearized Navier-Stokes equations which can be solved by using operator splitting algorithms too.Hence,a conjugate gradient method can be used to solve the optimal control problem.
文摘A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stator of a high pressure steam turbine. For comparison, we have studied the effects of bowed blades on the wakes of stator trailing edge and horse shoe vortex in the rotor. It was found that the position of wakes for bowed blades is shifted toward the blade suction side. Also, we have discussed and compared the entropy generation and energy loss caused by dissipation mechanism within the boundary layers on the hub and shroud; and temperature gradient in meridional plane.
