초록 ▼

A low-pressure turbine of a gas turbine is disclosed. The turbine comprises a number of stages arranged one behind the other in an axial manner in the flow-through direction of the turbine. Each stage is formed from a fixed vane ring having a number of vanes and from a rotating blade ring having a n

A low-pressure turbine of a gas turbine is disclosed. The turbine comprises a number of stages arranged one behind the other in an axial manner in the flow-through direction of the turbine. Each stage is formed from a fixed vane ring having a number of vanes and from a rotating blade ring having a number of blades. Each stage is characterized by a characteristic value vane-to-blade ratio that indicates the ratio of the number of vanes to the number of blades within a stage. One of the stages of the turbine is designed in such a manner that, in the event of noise-critical conditions of the turbine, the characteristic value vane-to-blade ratio of this stage is between a lower cut-off limit for mode k=−1 of the blade-passing frequency (BPF) of said stage and an upper cut-off limit for the mode k=−2 of the blade-passing frequency (BPF) of this stage.

대표청구항 ▼

What is claimed is: 1. A turbine, comprising: a plurality of stages positioned axially one behind the other in the flow direction of the turbine, each stage being formed by a stationary guide vane ring having multiple guide vanes and a rotating blade ring having multiple rotating blades, and each s

What is claimed is: 1. A turbine, comprising: a plurality of stages positioned axially one behind the other in the flow direction of the turbine, each stage being formed by a stationary guide vane ring having multiple guide vanes and a rotating blade ring having multiple rotating blades, and each stage having a vane-to-blade ratio characteristic quantity indicating a number of guide vanes to the number of rotating blades ratio within a stage; at least one stage of the plurality of stages of the turbine being designed so that under noise-critical operating conditions of the turbine, the vane-to-blade ratio characteristic quantity of the one stage is between a lower cut-off limit for the mode k=−1 of the blade-passing frequency of the one stage and an upper cut-off limit for the mode k=−2 of the blade-passing frequency of the one stage. 2. The turbine as recited in claim 1, wherein the one stage is an upstream stage. 3. The turbine as recited in claim 2, wherein the upstream stage has a vane-to-blade ratio characteristic quantity of between 0.6 and 0.8. 4. The turbine as recited in claim 3, wherein the vane-to-blade ratio characteristic quantity of the upstream stage is 0.7. 5. The turbine as recited in claim 1, wherein a further stage of the turbine is designed in such a way that its vane-to-blade ratio characteristic quantity is between a lower cut-off limit for the mode k=−1 of the double blade-passing frequency of the further stage and an upper cut-off limit for the mode k=−2 of the double blade-passing frequency of the further stage under noise-critical operating conditions of the turbine. 6. The turbine as recited in claim 5, wherein the further stage is a downstream stage. 7. The turbine as recited in claim 6, wherein a vane-to-blade ratio characteristic quantity of the downstream stage is between 1.3 and 1.5. 8. The turbine as recited in claim 7, wherein the vane-to-blade ratio characteristic quantity of the downstream stage is 1.4. 9. The turbine as recited in claim 6, wherein the upstream stages of the turbine positioned in the flow direction are designed in such a way that the vane-to-blade ratio characteristic quantities of the upstream stages are between 0.6 and 0.8, and the downstream stages of the turbine positioned in the flow direction are designed in such a way that the vane-to-blade ratio characteristic quantities of the downstream stages are between 1.3 and 1.5. 10. The turbine as recited in claim 9, wherein the vane-to-blade ratio characteristic quantities of the upstream stages are 0.7 and the vane-to-blade ratio characteristic quantities of the downstream stages are 1.4. 11. The turbine as recited in claim 1, wherein the upstream stages of the turbine positioned in the flow direction are designed in such a way that under noise-critical operating conditions of the turbine their vane-to-blade ratio characteristic quantity is between the lower cut-off limit for the mode k=−1 of the blade-passing frequency and the upper cut-off limit for the mode k=−2 of the blade-passing frequency and the downstream stages of the turbine positioned in the flow direction are designed in such a way that under noise-critical operating conditions of the turbine the vane-to-blade ratio characteristic quantity is between a lower cut-off limit for the mode k=−1 of the double blade-passing frequency and an upper cut-off limit for the mode k=−2 of the double blade-passing frequency. 12. The turbine as recited in claim 1, wherein the turbine is a low pressure turbine of a gas turbine. 13. The turbine as recited in claim 12, wherein the turbine is a turbine of an aircraft engine.