how to calculate the averaged mass flow along a line over time ?
 

Hi, everybody!
After my 2D case accomplished, i want to know the averaged mass flow along a specified line over time. i searched web for help, and found that the paraview3.8.1 has filter to calculate the mass flow.

First i selected the cells through the face, then extracted the selection and defined the calculate(mass flow). Finally, i chose the plot selection over time filter. But the filter just shows the value of only one cell, which is not averaging the total selected cells. Thus before the plot selection over time filter, i added the integrate variables filter.However, the integrate variables filter doesn't work properly, which calculates only one cell.

Is there any advise to my question? or any other way to calculate the averaged mass flow along a specified line over time? Thank you very much!