Mirror image flow detection method and virtual flowmeter

The invention belongs to the technical field of fluid flow, and particularly relates to a mirror image flow detection method, which comprises the following steps of: measuring pressure at front and rear ends of a pipeline and the flow of fluid in the pipeline; performing self-learning of flowability characteristic coefficients of the pipeline; calculating a mirror image flow value of the fluid inthe pipeline according to the obtained flowability characteristic coefficient domain and the pressure at the front and rear ends of the pipeline; and when determining that the flowability characteristic of a specified pipe section is not changed suddenly and that a flow value of the actual fluid in the monitored pipeline deviates and even is lost, selecting the mirror image flow value as a resultto be outputted. The invention also discloses a virtual flowmeter, which comprises at least two pressure sensors, a self-learning module and a virtual flowmeter module. The virtual flowmeter realizesthe embedding of a mirror image algorithm function, and achieves the redundant effect that the mirror image flow value becomes a shadow behind the fluid flow value gradually by the self-learning.