Oluwagbemiga Fabunmi

Can I ask you another question?  I am simulating flow through a porous medium using ANSYS Fluent. There is only one inlet and no outlet. However, when I view the CFD Post, I realize that the values for mass flow rate are all negative. This is strange to me because the vectors show that the flow is in the positive x direction as I'd set it up. Why are my mass flow rate values negative?