Runner cone separation in Kaplan turbines
2011 (English)In: 4-th International Meeting on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems,: October, 26-28, 2011, Belgrade, Serbia / [ed] A. Gajic; M. Benisek; M. Nedeljkovic., Belgrade: IAHR , 2011, 265-271 p.Conference paper (Refereed)
Low head machines of the Kaplan type are composed of several components to ensure high efficiency. Downstream the runner, a draft tube ensures pressure recovery of the flow leaving the runner. Modern draft tubes are mainly composed of a conical diffuser followed by an elbow and a straight diffuser. The runner cone, attached to the runner, is included in the conical diffuser and thus counter-acts the function of the draft tube since adding angular momentum to the fluid. Variation of the runner cone angular velocity may increase draft tube pressure recovery by delaying eventual separation. While previous research focused only on the draft tube flow, this work presents calculations including runner and draft tube in order to point out possible joint effects. The initial calculations with ω*=1 are validated by comparison of mean and angular resolved axial and tangential velocity with LDA measurements. Two runner cone angular velocities are simulated: ω*=-1 (counter-rotating) and ω*=0 (stationary). A significant efficiency increase is obtained for a stationary runner cone.
Place, publisher, year, edition, pages
Belgrade: IAHR , 2011. 265-271 p.
Research subject Fluid Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-39105Local ID: db7f98a5-613d-4c4f-8319-d29191f092fcISBN: 978-86-7083-740-9OAI: oai:DiVA.org:ltu-39105DiVA: diva2:1012614
International Meeting on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems : 26/10/2011 - 28/10/2011
Godkänd; 2011; 20111125 (ysko)2016-10-032016-10-03Bibliographically approved