The fossil fuels are depleting with time, hence the research work in the area of alternate energy is growing; thereby providing an abundant scope for biofuel production and deployment. It is well known that the fuel mixture directly affects the performance and efficiency of any automobile. The various physical properties that govern the fuel mixture are viscosity, concentration, additives, boiling point, melting point, etc. Hence, developing a sensor, based on such physical properties, can provide a reliable and effective solution to detect and monitor the biodiesel blending. This research paper describes the computational analysis of a Y -shaped microfluidic device which performs various fluidic operations by analyzing physical properties and their variations. The idea behind this study is to find out the adherence of the device to the Hagen-Poiseuille flow equation. The working principle in this case is concentration dependent width capture by the fluids flowing in the channels based on the pressure difference in the inlet and outlet ports. The different physical characteristics with their test results for various blending ratios of diesel with biodiesel have been shown in this study. Such microfluidic devices also have other viscosity based sensing and monitoring applications such as hemoglobin detection, food adulteration etc. © 2015 American Scientific Publishers All rights reserved.