Turbine Rotor Cooling Shield with Mixed Steam Flow
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Solution Overview
Problem
Steam turbines face high thermal loads due to high-temperature steam, leading to material stress, thermal distortion, and potential failure from cooling system malfunctions, which cause extreme thermal shocks and mechanical strain.
Innovation Solution
A turbomachine design with a shield that allows live steam to flow into the cooling area between the rotor and the shield, mixing with cooling steam to maintain a moderate temperature, reducing thermal stress and enabling passive cooling without complex control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cold reheater steam is used to cool the rotor in the inflow area, then the material temperature is reduced, but very large temperature differences occur leading to high thermal stresses and thermal distortion
Solution Approach 1:
The invention changes the temperature parameter of the cooling steam by mixing cold reheater steam with hot live steam. The shield has a first region receiving cold reheater steam and a second region receiving hot live steam, creating a temperature gradient that prevents excessive thermal stress while still cooling the rotor effectively
Solution Approach 2:
The shield is divided into different regions with different cooling qualities: a first region for strong cooling with cold reheater steam and a second region for moderate cooling with hot live steam. This local differentiation allows effective cooling where needed while avoiding thermal shock in other areas
2Temperature
If strong cooling with cold reheater steam is applied, then the rotor temperature is reduced, but in case of cooling system failure extreme thermal shocks occur
Solution Approach 1:
The invention prepares for cooling system failure by providing a backup cooling path through the second region of the shield that receives hot live steam. This passive backup ensures that even if the active cold reheater steam supply fails, the rotor will not experience extreme thermal shocks because the hot steam provides continuous moderate cooling
Solution Approach 2:
Hot live steam acts as an intermediary cooling medium that provides a fallback cooling mechanism. When the primary cold reheater steam cooling fails, the hot live steam through the second region of the shield serves as a mediator to prevent extreme temperature rise and thermal shock
3Productivity
If high inlet temperature steam is used to increase efficiency, then thermodynamic efficiency improves, but the thermal load on materials increases
Solution Approach 1:
The invention extracts hot live steam from the main flow path and redirects it through the second region of the shield to cool the rotor. This separates the high-temperature steam's work function (driving the turbine) from its thermal load effect (heating the rotor), allowing high efficiency operation while managing thermal load through dedicated cooling paths
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces thermal stress and mechanical strain, ensuring robust operation even in cooling system failures by maintaining a stable temperature and minimizing thermal expansion, thus preventing damage from extreme temperature fluctuations.
Implementation Method 1
a coolant feed which is designed in such a way that during operation a cooling steam in a cooling area which is arranged between the shield and the rotor flows
Implementation Method 2
a line which establishes a fluidic connection between the cooling area and the inflow area
Implementation Method 3
a shield which is designed in such a way that during operation a steam flowing into an inflow area can be deflected into a flow channel
Implementation Method 4
if the cooling system fails, the previously cooled shaft expands significantly
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a turbomachine, in particular a steam turbine (2, 12, 13), with a shield (27) and a coolant supply (36) which causes cold intermediate superheater steam to flow onto the rotor (21), wherein additionally supply holes are arranged in the shield (27), which holes bring part of the hot inflow steam into the cooling region (37) between the shield (27) and the rotor (21), in order to thus improve mixing so as to raise the temperature of the rotor (21) at this thermally loaded point, such that in the event of a fault (failure of the coolant line) the resulting change in temperature is moderate.