Impurity is one of the main factors that affect the measurement accuracy of an ultrasonic heat meter. To study the effects of different impurity species and concentrations on the accuracy of heat meters, flow tests we...Impurity is one of the main factors that affect the measurement accuracy of an ultrasonic heat meter. To study the effects of different impurity species and concentrations on the accuracy of heat meters, flow tests were carried out for the suspending of calcium carbonate and yellow mud. By analyzing the attenuation characteristics of the ultrasound amplitude in different impurity concentrations and species, the influence of the impurities on the heat meter measurement accuracy is evaluated. In order to avoid the inaccuracy caused by the sediment of the reflective bottom surface, a vortex generator is put ahead of the reflective surface. According to the test, the calcium carbonate suspension with a mass concentration of 1%, which influences the heat meter accuracy severely, is used as the flow media. The influence of the vortex generator on the calcium carbonate suspension flow field in the heat meter body is studied with numerical simulations. The results of this paper provide some theoretical guide on improving the heat meter measurement accuracy when the water contains impurities.展开更多
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
Based on a discrete phase model, the numerical simulation is carried out for the flow fields of different size calcium carbo- nate suspensions in the ultrasonic heat meter body. The flow characteristics and the impuri...Based on a discrete phase model, the numerical simulation is carried out for the flow fields of different size calcium carbo- nate suspensions in the ultrasonic heat meter body. The flow characteristics and the impurity distribution in the ultrasonic heat meter body are analyzed. The errors of the ultrasonic heat meter in measuring calcium carbonate suspensions of particles of 10 micrometers and the causes are analyzed by simulation and experiment. Results show the effects of the impurities on the value of the k coeffi- cient and the sound attenuation on the reflection path due to the particle distribution are the two main factors that influence the mea- surement accuracy.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51276102)the Natural Science Foundation of Shandong Province(Grant No.ZR2014EEM015,ZR2011EEM011.)
文摘Impurity is one of the main factors that affect the measurement accuracy of an ultrasonic heat meter. To study the effects of different impurity species and concentrations on the accuracy of heat meters, flow tests were carried out for the suspending of calcium carbonate and yellow mud. By analyzing the attenuation characteristics of the ultrasound amplitude in different impurity concentrations and species, the influence of the impurities on the heat meter measurement accuracy is evaluated. In order to avoid the inaccuracy caused by the sediment of the reflective bottom surface, a vortex generator is put ahead of the reflective surface. According to the test, the calcium carbonate suspension with a mass concentration of 1%, which influences the heat meter accuracy severely, is used as the flow media. The influence of the vortex generator on the calcium carbonate suspension flow field in the heat meter body is studied with numerical simulations. The results of this paper provide some theoretical guide on improving the heat meter measurement accuracy when the water contains impurities.
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.
基金Project supported by the National Natural Science Foundation of China(Grant No.51276102)
文摘Based on a discrete phase model, the numerical simulation is carried out for the flow fields of different size calcium carbo- nate suspensions in the ultrasonic heat meter body. The flow characteristics and the impurity distribution in the ultrasonic heat meter body are analyzed. The errors of the ultrasonic heat meter in measuring calcium carbonate suspensions of particles of 10 micrometers and the causes are analyzed by simulation and experiment. Results show the effects of the impurities on the value of the k coeffi- cient and the sound attenuation on the reflection path due to the particle distribution are the two main factors that influence the mea- surement accuracy.
