DETERMINING AN ACTUAL VALUE AND OR AN ACTUAL VALUE RANGE OF AT LEAST ONE STATE VARIABLE OF A FLUID IN A FLUID FLOW BY MEANS OF AT LEAST ONE INDICATOR PARTICLE

摘要

The invention relates to a method for determining an actual value and/or an actual value range of at least one state variable of a fluid in a fluid flow by means of at least one indicator particle (9) introduced into the fluid. In addition, it is proposed that the at least one indicator particle (9) is designed and provided for an irreversible property change of an indicator property of the indicator particle (9) in the case of a certain indicator value of the at least one state variable in the fluid flow and/or as a clear function of the actual value when a certain time period has elapsed after the indicator particle (9) has been introduced into the fluid, wherein the indicator particle (9) is detected at a detection point, the indicator property of the indicator particle (9) is evaluated and the actual value and/or the actual value range of the state variable is inferred from the indicator property downstream of the detection point. The invention also relates to a method for operating a fluid-guiding device (7), an indicator particle (9) and a device (7) for determining the actual value and/or actual value range of the at least one state variable.