Ro­ta­tion­al Vi­bra­tions in Tur­bines

Tech­ni­cal phe­nom­e­na in gas and steam tur­bines

Ro­ta­tion­al vi­bra­tions or tor­sion­al vi­bra­tions are gen­er­al­ly de­fined as the vi­bra­tions of a sys­tem around a ro­ta­tion­al de­gree of free­dom. Thus at first lin­ear elas­tic os­cil­la­tions around the own body axis. Nowa­days, vi­bra­tion phe­nom­e­na such as ro­ta­tion­al vi­bra­tions play an enor­mous role in mod­ern tur­bines, whether gas tur­bines or steam tur­bines. The de­vel­op­ment tends to con­struct ever larg­er tur­bines with a high­er ef­fi­cien­cy. Sim­i­lar­ly, as the size and com­plex­i­ty of a tur­bine in­creas­es, so does the in­flu­ence of dan­ger­ous vi­bra­tion con­di­tions on the safe­ty of the en­tire sys­tem.

Net-In­duced Tor­sion­al Loads

Chal­lenges due to ro­ta­tion­al vi­bra­tions

One of the big­gest chal­lenges in the op­er­a­tion of a tur­bine is fre­quen­cy fluc­tu­a­tions in the grid sup­ply, as these can pro­mote the oc­cur­rence of forced ro­ta­tion­al vi­bra­tions in the main shaft of a tur­bine. More specif­i­cal­ly, these vi­bra­tions are caused by dif­fer­ent fed-back in­duced tor­sion­al loads on the tur­bine, com­pres­sor and gen­er­a­tor.

The forced tor­sion­al vi­bra­tions rep­re­sent a dan­ger pre­cise­ly when their phase or op­er­at­ing speed co­in­cides ap­prox­i­mate­ly or com­plete­ly with the phase of the sys­tem's nat­u­ral vi­bra­tions. In en­gi­neer­ing, this phe­nom­e­non is called a res­o­nance catas­tro­phe. An un­damped sys­tem re­acts to even the small­est ex­ter­nal ex­ci­ta­tion with strong­ly in­creas­ing os­cil­la­tion de­flec­tions. The ini­tial­ly elas­tic ro­ta­tion­al vi­bra­tions be­come loads that lead to the break­age of the tur­bine shafts.

Mea­sure­ment and Anal­y­sis Tech­nol­o­gy for a Safe Oper­a­tion

Our so­lu­tion for pro­tec­tion against ro­ta­tion­al vi­bra­tions

A mea­sure­ment and anal­y­sis sys­tem that mon­i­tors the nat­u­ral fre­quen­cies of the sys­tem and thus en­sures op­er­a­tion out­side the crit­i­cal op­er­at­ing ranges. In crit­i­cal sit­u­a­tions, an im­me­di­ate safe­ty shut­down is ini­ti­at­ed. This pre­vents cost­ly dam­age and down­time.

The IfTA Ar­gusOMDS, our all-in-one so­lu­tion in com­bi­na­tion with the award-win­ning AT2 input mod­ule and the anal­y­sis soft­ware IfTA TrendView­er, meets pre­cise­ly these re­quire­ments. The cus­tom­iz­a­ble sys­tems en­able angle-re­lat­ed eval­u­a­tions of ro­ta­tion­al and tor­sion­al vi­bra­tions in real time. In this way, the dif­fer­ent nat­u­ral fre­quen­cies of the tor­sion­al vi­bra­tions of the tur­bine can be mon­i­tored and dan­ger­ous vi­bra­tion states avoid­ed. The in­te­grat­ed real-time anal­y­sis im­me­di­ate­ly ini­ti­ates nec­es­sary pro­tec­tive mea­sures in crit­i­cal op­er­at­ing areas.

 

Hands-on-knowl­edge: Mea­sure­ment setup tor­sion­al vi­bra­tions

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High Speed Timer AT2

Flex­i­ble and fast timer mod­ule with two ana­log in­puts.

Ar­gusOMDS

Pro­tec­tion sys­tem with di­ag­nos­tic and mon­i­tor­ing func­tion­al­i­ty.

Dy­naMaster

Di­ag­nos­tic tool for high-speed anal­y­sis & in­tel­li­gent vi­su­al­iza­tion.

TrendView­er

Fast & in­­­tu­it­ive on­­line/of­f­­line ana­lys­is soft­­ware for ef­­fi­­cient vi­su­al­iz­a­­tion.