Mass Flow Monitoring by Distributed Fiber Optical Temperature Sensing

We developed a novel method to monitor mass flow based on distributed fiber optical temperature sensing. Examination of the temporal and spatial temperature distribution along the entire length of a locally heated fluidic conduit reveals heat flow under forced convection. Our experimental results are in good agreement with two-dimensional finite element analysis that couples fluid dynamic and heat transfer equations. Through analysis of the temperature distribution bidirectional flow rates can be measured over three orders of magnitude. The technique is not flow intrusive, works in harsh conditions, including high-temperatures, high pressures, corrosive media, and strong electromagnetic environments. We demonstrate a first experimental implementation on a short fluidic system with a length of one meter. This range covers many applications such as low volume drug delivery, diagnostics, as well as process and automation technology. Yet, the technique can, without restrictions, be applied to long range installations. Existing fiber optics infrastructures, for instance on oil pipelines or down hole installations, would only require the addition of a heat source to enable reliable flow monitoring capability.