Rotor Dynamics Analysis for Multiple Rotors
Hello, I have a model that consist of multiple rotor which have different RPM's. These are connected each other with RGB's (Reduction Gear Box). I defined 3 different ROTORG Set for components that have different speed. But under loadstep I can choose just one RGYRO card. As you know RGYRO card includes ROTORG set. Shortly, how can I define the different RPM rotors in one analysis model. Thanks for your responses.
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Thanks for your answer. I had reviewed the part you posted in the help section. Actually, what I was wondering was if we examine the ROTOR_1, ROTOR_2 and ROTOR_3 set with SPTID values of 1.0, 2.0 and 3.0 respectively; let's take the ROTOR_1 set as a reference. I also defined the RSPEED card that includes RPM increases in a certain range. When the RSPEED value is 3000 RPM, the speed values for ROTOR_2 and ROTOR_3 will be 6000 RPM and 9000 RPM, is that correct?
If so, when I select the ROTOR_3 set as a reference and in the same way when the RSPEED value is 3000 RPM; will the speed values for ROTOR_1 and ROTOR_2 be 1000 RPM and 2000 RPM, respectively?
Finally, I could not fully understand from the help section in which cases the DDVAL definition is necessary in rotor dynamics. I would be very happy if you could make an explanation for this, thank you, good work.
When multiple rotors are present within the system being modeled, one of the rotors is chosen as a reference rotor. The speeds of the rest of the rotors are linearly dependent of the reference rotor. Scale factors
S1and
S2are used to relate the speeds.
(1)Ω=S1+S2*ΩrefΩ=S1+S2*ΩrefWhere,ΩSpeed of a rotor (different from the reference rotor)S1andS2Scale factorsΩrefSpeed of the reference rotorhttps://2021.help.altair.com/2021/hwsolvers/os/topics/solvers/os/rgyro_bulk_r.htm