This paper studies an annular geometry for thermo-rheological analysis of a polymer flow. In polymer processing, it is necessary to have a good knowledge of the material’s thermo-rheological properties and the processing conditions. However, the material’s properties depend on the processing conditions, not to mention recycled and bio-sourced materials with fluctuating and poorly understood characteristics. Moreover, the viscous heating of a polymer flow can modify processing temperature. There is a real need for in-line/on-line thermo-rheological measurements to make production more flexible and responsive to raw materials’ condition. Currently on a polymer production line (injection, extrusion…), we only have access to the pressure measurements at the entrance of the flow. Sometimes they are completed by non-intrusive temperature measurements, which can be easily disturbed by the wall temperature of the tool. A few studies reveal the interest and the difficulty to access to the thermal measurements of the polymer flow for in-line/on-line monitoring. In this work, an analytical and numerical study is carried out to examine the possibility to measure the polymer’s temperature increasing all along the annular channel due to the viscous dissipation. The results show that the annular geometry contributes to a high concentration of viscous dissipation at the central axis, compared to a cylindrical geometry subjected to the same external mechanical power. In addition, under the production conditions, the polymer flow with a large Péclet number isolates the central axis from external thermal disturbances. It is thus possible to measure robustly at the center of the flow the temperature variation with respect to the change in thermo-rheological parameters, which opens up new perspectives for an in-line/on-line characterization method.