Closed Loop Self Regulating Mud Turbine
Publication Date: 2004-Oct-14
The IP.com Prior Art Database
1 Abstract A turbine for driving means that consume mechanical power in a downhole drilling tool, e. g. an electric generator, the turbine comprising a turbine housing and a guide wheel having a flow passage for guiding the incoming flow in a rotational manner, a turbine wheel having blades to which the rotational flow is supplied from said flow passage, wherein the turbine wheel includes means actuated by magnetic force receiving power upon an increase in the rotational speed of the turbine for uniformly redirecting the rotating flow to lower rotational speed of the flow passage to all of said turbine blades and thus the amount of rotational energy acting on the blades of the turbine wheel is lowered to an extent depending upon the rotational speed of the turbine wheel. The turbine wheel is an axial turbine wheel having a protruding central hub portion carrying one side of the magnetic actuator. The incoming flow is incident upon the guide blades causing the flow to be rotationally excited by the guide blades and thereafter flows past the turbine wheel along the axial direction. The magnetic force actuated means comprises a lever attached to the end of the guide vane causing to deflect the vanes to reduce the rotational excitation of the flow. The no load turbine speed is mainly affected by the radial component of fluid velocity (u) and the geometry of the rotor. While the geometry of the rotor is not being changed in this application, the blade angle change of the guide wheel causes the radial component of fluid velocity (u) to be accelerated or decelerated with changes in c1. Another aspect in turbine layout is the hydraulic moment and therefore the possible power of a mud turbine. On the design concept side this is determined by the vane angles, i.e. the outlet angle of the guide vane (α1), the inlet angle of the rotor (ß1) and the outlet angle of the rotor (ß2). Of course several more parameters like turbine radius or mass flow have direct influence on the turbine performance. In this application only the change in the outlet angle of the guide vane (α1) will be described in regards to turbine speed and performance.