Flow modeling of continuous Indian unleavened flat bread (chapatis) former Original Research Article

A mathematical model was developed to predict the flow rate and torque requirements in continuous Indian unleavened flat bread (chapatis) forming system, based on mechanical extrusion. Variables included were screw speed, length to die width, and product moisture. Flow rate and torque were effected by product moisture and die width. For a constant pressure drop, flow rate increased as die width and product moisture increased. The flow rate and torque equations used for modeling were:Q=G1NFdt(1−δ/H)+G2Fpt/μ(P1−P2)/L(1+f)and τ=G3N(G4μ+G5μδ)+G6(P2−P1), respectively where Q is the volumetric flow rate, τ the torque input, N the screw speed, Fdt the total drag flow, Fpt the total pressure flow, δ the flight clearance, H the channel depth, μ viscosity of dough in the channel, μδ viscosity in the flight clearance, P1 dough pressure at input end, P2 dough pressure at output end, L the length of extrusion section under study in axial direction, f correction for pressure flow and G1–G6 are the constants.