  Flow sensors have diverse applications in the field of biomedical engineering
and also in industries. Micromachining of flow sensors has accomplished a new
goal when it comes to miniaturization. Due to the scaling in dimensions, power
consumption, mass cost, sensitivity and integration with other modules such as
wireless telemetry has improvised to a great extent. Thermal flow sensors find
wide applications in biomedical such as in hydrocephalus shunts and drug
delivery systems. Infrared thermal sensing is used for preclinical diagnosis of
breast cancer, for identifying various neurological disorders and for
monitoring various muscular movements. In this paper, various modes of thermal
flow sensing and transduction methods with respect to different biomedical
applications are discussed. Thermal flow sensing is given prime focus because
of the simplicity in the design. Finally, a comparison of flow sensing
technologies is also presented.
