Frequency response function of Structures to spatial fluctuations of fluid temperature

kasahara, Naoto; not registered

Temperature fluctuation from incomplete fluid mixing induces fatigue damages on structures of nuclear components, which should be prevented. For rational analyses of this phenomenon, the authors have developed a frequency response function of thermal stress induced by fluid temperature fluctuations on the fixed spatial boundary. 0n the other hand, actual components have other stress generation modes from multi-dimensional spatial fluctuations of fluid temperature such as traveling of thermal stratification layers and hot/cold spots. This study has extended the frequency response function to be applied to spatial fluctuations problems of fluid temperature. Different characteristics of spatial fluctuation problems from fixed ones are their stress dependencies on both frequencies and traveling distances. When the distance is long and the frequency is very low, thermal stress is not attenuated. At actual components, stresses usually attenuate because the distances are short and frequencies are high. A proposed frequency response function rationally evaluates thermal stress induced by spatial traveling according to their traveling distances and frequencies.