Liquid cooled electrical machine
Flow control apparatus for an electrical machine and comprising an arrangement of shaped chambers and passages for conveying a liquid coolant. The rate of heat transfer from certain portions of the machine to the coolant is determined by the varying velocity of the liquid through the chambers, resulting in a generally uniform cooling of those portions of the machine.
1. A flow control apparatus for an electrical machine and comprising:
a first wall and a second wall, the second wall being inclined with respect to the first wall so as to define a tapered first chamber between the first and second walls, the first chamber including an entrance aperture and an exit aperture wherein;
in use the taper causes the velocity of a liquid in the first chamber to be varied as the liquid is conveyed between the entrance aperture and the exit aperture, such that a transfer of thermal energy from a heat source to the liquid via the first wall is substantially uniform between the entrance aperture and the exit aperture.
2. The flow control apparatus as claimed in claim 1
wherein:
the second wall comprises a guide member, the guide member having a first face and a second face, the first face being inclined with respect to the second face so as to form a tapered profile between the first and second faces,
and wherein;
the tapered first chamber is defined by the first wall and the first face of the guide member.
3. The flow control apparatus as claimed in claim 2 and further comprising:
a third wall comprising a flow path, the flow path being arranged to receive a liquid; and
a second chamber, defined by the third wall and the second face of the guide member, the exit aperture of the first chamber being coupled to the second chamber wherein;
in use the liquid is conveyed from the first chamber to the second chamber via the exit aperture and at least a portion of the liquid in the second chamber is diverted onto the flow path.
4. The flow control apparatus as claimed in claim 1 wherein the first wall comprises an undulated surface suitable for inducing turbulence in the liquid.
5. The flow control apparatus as claimed in claim 2 wherein the first face of the guide member comprises an undulated surface suitable for inducing turbulence in the liquid.
6. The flow control apparatus as claimed in claims 3 wherein the first face of the guide member comprises an undulated surface suitable for inducing turbulence in the liquid.