Study on the fluid dynamics of nitrogen and hydrogen gases subjected to wires element in monolithic channel

Abstract

Abstract. Ammonia has a very significant value in the fertilizer industry where it was being synthesized via Haber-Bosch process in the early 19th century. As the process utilize high operating conditions, it imposes high capital cost and is an energy-consuming process. Due to this unsustainable process, researchers have initiated an alternative to overcome this drawback by performing a simulation in microfluidic environment using ambient temperature and pressure (25 o C and 1 atm). Wires element configured in a 50 mm x 10 mm, (L x D) dimension monolithic channel with different spacing and number of wires, arranged axially in 60 o pitch have been introduced to investigate the dynamic mixing of nitrogen and hydrogen for ammonia synthesis. As the wires are configured in a different manner, the results show dissimilar volume fraction profile, contours and mixing index. Creating suitable obstruction with larger obstruction space enhanced the mixing. Reducing spacing from 2 mm to 1.5 mm illustrates fluctuating velocity at the centre of the channel causing the flow velocity become less than the set velocity 0.05ms -1 . By substituting from 19 wires to 13 wires to the flow, chaotic advection occurs lead to the increased of mixing index up to 94%.Keywords. monolithic channel / computational fluid dynamic / dynamic mixing / ANSYS CFX / ammonia