Turbine Test Rig Torque Arm Hydraulic Cylinder Yaw Force Compensation
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Solution Overview
Problem
Existing test rigs for turbines generate unwanted yaw forces due to the reaction torque taken by the surrounding construction, which falsifies test results and simulates forces inaccurately.
Innovation Solution
A double torque arm and double cylinder construction is used, where two hydraulic cylinders with fluid chambers are coupled via hoses to balance the reaction torque, eliminating unwanted yaw forces by maintaining equal pressure across the system, and allowing for variable length adjustments to accommodate tilting forces without exerting additional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single torque arm is used to take reaction torque, then the reaction torque can be taken, but unwanted yaw forces are generated that falsify test results
Solution Approach 1:
The single torque arm is divided into two torque arms arranged symmetrically on opposite sides of the shaft. Each torque arm is connected to its own hydraulic cylinder, creating a segmented system that distributes the reaction torque taking function across multiple independent elements, thereby eliminating the generation of unwanted yaw forces.
Solution Approach 2:
The two torque arms are positioned asymmetrically relative to the shaft centerline but symmetrically relative to each other, with each arm connected to a separate hydraulic cylinder. This asymmetric arrangement of identical components allows the system to take reaction torque while maintaining force balance and avoiding unwanted yaw moments.
2Force
If hydraulic cylinders are used to take reaction torque, then torque can be balanced, but the system becomes more complex
Solution Approach 1:
The hydraulic cylinders of the two torque arms are connected through common fluid chambers and hoses, merging the hydraulic systems into a single integrated unit. This allows the cylinders to work together as a coordinated system for taking reaction torque, reducing overall complexity compared to completely independent systems.
Solution Approach 2:
The hydraulic cylinder arrangement serves multiple functions: it takes reaction torque from the drive motor, balances forces on both sides of the shaft, and provides a unified support structure. The same hydraulic system simultaneously performs torque taking and force balancing functions for both torque arms.
3Force
If the torque arm is fixed to ground, then reaction torque can be taken, but the test accuracy is reduced due to unwanted reaction forces
Solution Approach 1:
The two torque arms with their respective hydraulic cylinders act as counterbalancing elements. When one torque arm experiences a reaction force, the other torque arm experiences an opposing reaction force of equal magnitude, creating a counterweight effect that cancels out unwanted yaw forces and protects the test accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for reaction torque without generating unwanted yaw forces, ensuring accurate simulation of real-world loads on the turbine, thereby improving the reliability of test results.
Implementation Method 1
two hydraulic cylinders with fluid chambers are coupled via hoses to balance the reaction torque
Implementation Method 2
maintaining equal pressure across the system
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Test rig for a back-to-back test of a turbine, comprising a generator and a drive motor driving the generator, a shaft coupled to the drive motor and to a surrounding construction for taking a reaction torque created by the driven generator and received by the shaft, and a load cylinder arrangement coupled to the shaft, whereby the surrounding construction comprises two hydraulic cylinders (8a, 8b) each being coupled to a radial torque arm (7a, 7b) projecting oppositely to different sides from the shaft (10), each cylinder (8a, 8b) comprising a first and a second fluid chamber (15a, 16a, 15b, 16b) divided from each other by a piston (19a, 19b) and changing their volume when the shaft is loaded due to receiving a reaction torque, with the first chamber (15a) of the first cylinder (8a) being coupled to the second chamber (16b) of the second cylinder (8b) by means of a fluid hose (17) and with the second chamber (16a) of the first cylinder (8a) being coupled to the first chamber (15b) of the second cylinder (8b) by means of another fluid hose (18).