Njengomthombo wamandla avuselelekayo ophendula ngokukhawuleza, amandla ombane adla ngokudlala indima yokulawula okuphezulu kunye nokulawula amaza kwigridi yamandla, oko kuthetha ukuba iiyunithi zamandla ombane zihlala zifuna ukusebenza phantsi kweemeko ezichasene neemeko zoyilo. Ngokuhlalutya inani elikhulu ledatha yovavanyo, kucacisiwe ukuba xa i-turbine isebenza phantsi kweemeko ezingezizo ezoyilo, ingakumbi phantsi kweemeko zomthwalo ongaphelelanga, i-pulsation enamandla yoxinzelelo iya kuvela kwi-draft tube ye-turbine. I-frequency ephantsi yale pressure pulsation iya kuchaphazela kakubi ukusebenza okuzinzileyo kwe-turbine kunye nokhuseleko lweyunithi kunye ne-workshop. Ke ngoko, i-pressure pulsation ye-draft tube iye yaxhalatyiswa kakhulu lishishini kunye nezemfundo.
Ekubeni ingxaki yoxinzelelo lwe-pulsation kwi-draft tube ye-turbine yaqala ukucetywa ngo-1940, unobangela uye waxoxwa ngawo zizazi ezininzi. Okwangoku, izazi ngokubanzi zikholelwa ukuba uxinzelelo lwe-draft tube phantsi kweemeko zomthwalo ongaphelelanga lubangelwa yintshukumo ye-spiral vortex kwi-draft tube; ubukho be-vortex benza usasazo loxinzelelo kwicandelo elinqamlezileyo le-draft tube lungalingani, kwaye ngokujikeleza kwebhanti ye-vortex, intsimi yoxinzelelo engalinganiyo nayo iyajikeleza, nto leyo ebangela ukuba uxinzelelo lutshintshe rhoqo ngokuhamba kwexesha, nto leyo eyenza i-pressure pulsation. I-helical vortex ibangelwa kukuhamba okujikelezayo kwindawo yokungena ye-draft tube phantsi kweemeko zomthwalo ongaphelelanga (oko kukuthi, kukho icandelo le-tangential le-velocity). I-US Bureau of Reclamation yenze uphando lovavanyo kwi-swirl kwi-draft tube, yaza yahlalutya imo ye-vortex kunye nokuziphatha phantsi kwee-swirl degrees ezahlukeneyo. Iziphumo zibonisa ukuba kuphela xa i-swirl degree ifikelela kwinqanaba elithile, i-spiral vortex band iya kuvela kwi-draft tube. I-helical vortex ivela phantsi kweemeko zomthwalo ongaphelelanga, ngoko ke kuphela xa izinga lokuhamba elihambelanayo (Q/Qd, Qd lizinga lokuhamba kwephuzu loyilo) lomsebenzi we-turbine liphakathi kwe-0.5 kunye ne-0.85, i-pulsation yoxinzelelo olukhulu iya kuvela kwi-draft tube. I-frequency yecandelo eliphambili le-pressure pulsation ebangelwa yi-vortex belt iphantsi kakhulu, elingana ne-0.2 ukuya kwi-0.4 ye-rotation frequency ye-runner, kwaye i-Q/Qd encinci, kokukhona i-pressure pulsation frequency iphezulu. Ukongeza, xa i-cavitation isenzeka, amaqamza omoya aveliswa kwi-vortex aya kwandisa ubungakanani be-vortex kwaye enze i-pressure pulsation ibe namandla ngakumbi, kwaye i-frequency ye-pressure pulsation nayo iya kutshintsha.
Phantsi kweemeko zomthwalo ongaphelelanga, ukutyhafa koxinzelelo kwityhubhu yombane kungabeka umngcipheko omkhulu ekusebenzeni okuzinzileyo nokukhuselekileyo kweyunithi yombane wamanzi. Ukuze kuthintelwe oku kutyhafa koxinzelelo, kuye kwacetyiswa iingcamango ezininzi kunye neendlela, ezinje ngokufaka amaphiko eludongeni lwetyhubhu yombane kunye nokungena kwityhubhu yombane ngamanyathelo amabini asebenzayo. UNishi et al. basebenzise iindlela zovavanyo kunye namanani ukufunda isiphumo samaphiko kwi-pulsation yoxinzelelo lwetyhubhu yombane, kubandakanya iziphumo zeentlobo ezahlukeneyo zamaphiko, iziphumo zenani lamaphiko kunye neendawo zokufakelwa kwazo. Iziphumo zibonisa ukuba ukufakwa kwamaphiko kunokunciphisa kakhulu ukuxhaphaka kwe-vortex kunye nokunciphisa ukuxhaphaka koxinzelelo. UDmitry et al bafumanise ukuba ukufakwa kwamaphiko kunokunciphisa ubukhulu be-pulsation yoxinzelelo ngama-30% ukuya kuma-40%. Umoya ovela kumngxuma ophakathi we-shaft ephambili ukuya kwityhubhu yombane kukwayindlela esebenzayo yokuthintela ukuxhaphaka koxinzelelo. Ubungakanani bokuxhaphaka kwe-vortex. Ukongeza, uNishi et al. Ndizamile nokufaka umoya kwityhubhu yokutsala umoya ngemingxunya emincinci kumphezulu wephiko, ndaza ndafumanisa ukuba le ndlela inokucinezela uxinzelelo lwegazi kwaye umlinganiselo womoya ofunekayo umncinci kakhulu xa iphiko lingasebenzi.
Ixesha lokuthumela: Agasti-09-2022
