تحليل تنش ديسك دوجانه در روتور توربين خنك شونده با هواي سرد

Stress analysis of twin web disk in cooled turbine rotor with cooling air

اﺳﺘﻔﺎده از دﯾﺴﮏ ﻫﺎي دوﺟﺎﻧﻪ ﺑﻪ ﺟﺎي دﯾﺴﮏ ﻫﺎي ﺗﮏ ﺟﺎﻧﻪ در روﺗﻮر ﺗﻮرﺑﯿﻦ، اﯾﺪه ﻧﻮﯾﻨﯽ اﺳﺖ ﮐﻪ ﺑﻪ ﺳﺒﺐ اﯾﺠﺎد ﻓﻀﺎي ﻻزم، اﻣﮑﺎن ﺧﻨﮏ ﮐﺎري روﺗﻮر و در ﻧﺘﯿﺠﻪ ﮐﺎﻫﺶ ﺳﻄﺢ دﻣﺎ و ﺗﻨﺶ ﻫﺎي ﻧﺎﺷﯽ از آن را ﻓﺮاﻫﻢ ﻣﯽ ﮐﻨﺪ. دﯾﺴﮏ ﺗﺤﺖ ﺑﺎرﮔﺬاري ﻫﺎي ﻣﮑﺎﻧﯿﮑﯽ و ﺣﺮارﺗﯽ ﻗﺮار دارد. ﺑﺎرﮔﺬاري ﻣﮑﺎﻧﯿﮑﯽ ﺷﺎﻣﻞ اﺛﺮ ﻧﺎﺷﯽ از دوران دﯾﺴﮏ و ﺑﺎر ﮔﺮﯾﺰ از ﻣﺮﮐﺰ ﻧﺎﺷﯽ از دوران ﭘﺮه ﻫﺎ اﺳﺖ. ﺑﺎرﮔﺬاري ﺣﺮارﺗﯽ در اﺛﺮ ﺗﻐﯿﯿﺮات ﺣﺮارﺗﯽ ﻣﻮﺟﻮد ﺑﯿﻦ ﺳﻄﻮح داﺧﻠﯽ و ﺧﺎرﺟﯽ ﺑﺮ دﯾﺴﮏ اﻋﻤﺎل ﺷﺪه اﺳﺖ. ﺷﺮاﯾﻂ ﻣﺮزي دﯾﺴﮏ ﺑﻪ ﺻﻮرت دوﺳﺮﮔﯿﺮدار در ﻧﻈﺮ ﮔﺮﻓﺘﻪﺷﺪه اﺳﺖ. اﺑﺘﺪا ﺑﺎ اﺳﺘﻔﺎده از روش ﺣﻞ ﺗﺤﻠﯿﻠﯽ ﺗﺌﻮري اﻻﺳﺘﯿﺴﯿﺘﻪ ﺻﻔﺤﻪ اي رواﺑﻂ ﺣﺎﮐﻢ ﺑﺮ ﯾﮏ دﯾﺴﮏ دوار ﺗﮏ ﺟﺎﻧﻪ در ﺣﺎﻟﺖ ﺗﻨﺶ ﺻﻔﺤﻪ اي اﺳﺘﺨﺮاج ﺷﺪه اﺳﺖ. در اداﻣﻪ دﯾﺴﮏ ﻣﻮرد ﻧﻈﺮ ﺑﺎ ﭘﺮوﻓﯿﻞ ﺿﺨﺎﻣﺖ واﻗﻌﯽ ﺑﺎ اﺳﺘﻔﺎده از روش ﻋﺪدي ﺗﯿﻤﻮﺷﻨﮑﻮ-ﮔﺮﯾﻤﻞ ﻣﻮرد ﺗﺤﻠﯿﻞ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﺳﭙﺲ ﺑﻪ ﻣﻨﻈﻮر رﺳﯿﺪن ﺑﻪ ﯾﮏ دﯾﺴﮏ دوﺟﺎﻧﻪ ﺑﺎ ﭘﺮوﻓﯿﻞ ﻣﻨﺎﺳﺐ اﯾﻦ دﯾﺴﮏ ﺑﺎ ﺳﻮراخ ﻫﺎي ﭘﻠﻪ اي ﺷﮑﻞ در 400 ﺣﺎﻟﺖ ﻫﻨﺪﺳﯽ ﻣﺨﺘﻠﻒ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ و ﺣﺎﻟﺖ داراي ﮐﻤﺘﺮﯾﻦ ﺟﺮم ﻣﻤﮑﻦ و ﺿﺮﯾﺐ اﻃﻤﯿﻨﺎن ﻗﺎﺑﻞ ﻗﺒﻮل ﺑﻪ دﺳﺖ آﻣﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺗﺤﻠﯿﻞ ﻧﺸﺎن دﻫﻨﺪه ﮐﺎﻫﺶ ﺟﺮم، ﮐﺎﻫﺶ ﺳﻄﺢ ﺗﻨﺶ ﻫﺎ و ﺑﻬﺒﻮد ﺿﺮﯾﺐ اﻃﻤﯿﻨﺎن در اﺛﺮ اﺳﺘﻔﺎده از ﯾﮏ دﯾﺴﮏ دوﺟﺎﻧﻪ ﺑﻬﯿﻨﻪ ﻣﯽ ﺑﺎﺷﺪ.

Using twin web disks instead of single disks in turbine rotor is the new idea, which provides the necessary space for cooling and thus reducing the temperature level and the resulting stresses. The disk is subject to mechanical and thermal loading. Mechanical loading involves the effect of the disk rotation and the centrifugal load caused by the blade rotation at the external surface. Thermal loading is applied due to thermal changes between the internal and external surfaces on the disk. Disk boundary conditions are considered as dual-cantilever. Using the analytical solution method, the theory of elasticity of the plate is derived from the relations that govern the thickness of a rotating disk in a plane stress state. In the following, the disk was analysed under consideration the actual thickness profile using the Timoshenko- Grameel’s numerical method. In order to reach a twin web disk with a proper profile, this disk is studied with stepped holes in 400 different geometrical modes, and the state with the lowest possible mass and acceptable reliability coefficient is obtained. The results of the analysis show the reduction of mass, reduction of stress levels and improvement of the coefficient of confidence through the use of an optimal twin web disk.