The measurement accuracy of an ultrasonic heat meter depends on the relationship of the profile-linear average velocity.There are various methods for the calculation of the laminar and turbulence flow regions,but few ...The measurement accuracy of an ultrasonic heat meter depends on the relationship of the profile-linear average velocity.There are various methods for the calculation of the laminar and turbulence flow regions,but few methods for the transition region.At present,the traditional method to deal with the transition region is to adopt the relationship for the turbulent flow region.In this article,a simplified model of the pipe is used to study the characteristics of the transition flow with specific Reynolds number.The k-εmodel and the Large Eddy Simulation（LES）model are,respectively,used to calculate the flow field of the transition region,and a comparison with the experiment results shows that the LES model is more effective than the k-εmodel,it is also shown that there will be a large error if the relationship based on the turbulence flow is used to calculate the profile-linear average velocity relationship of the transition flow.The profile-linear average velocity for the Reynolds number ranging from 5 300 to 10 000 are calculated,and the relationship curve is obtained.The results of this article can be used to improve the measurement accuracy of ultrasonic heat meter and provide a theoretical basis for the research of the whole transition flow.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10972123, 10802042)the Natural Science Foundation of Shandong Province (Grant No. Y2007A04)
文摘The measurement accuracy of an ultrasonic heat meter depends on the relationship of the profile-linear average velocity.There are various methods for the calculation of the laminar and turbulence flow regions,but few methods for the transition region.At present,the traditional method to deal with the transition region is to adopt the relationship for the turbulent flow region.In this article,a simplified model of the pipe is used to study the characteristics of the transition flow with specific Reynolds number.The k-εmodel and the Large Eddy Simulation（LES）model are,respectively,used to calculate the flow field of the transition region,and a comparison with the experiment results shows that the LES model is more effective than the k-εmodel,it is also shown that there will be a large error if the relationship based on the turbulence flow is used to calculate the profile-linear average velocity relationship of the transition flow.The profile-linear average velocity for the Reynolds number ranging from 5 300 to 10 000 are calculated,and the relationship curve is obtained.The results of this article can be used to improve the measurement accuracy of ultrasonic heat meter and provide a theoretical basis for the research of the whole transition flow.
