You are to design a 45 mm diameter square pitch single screw extruder.

A. If melting starts after turn 5, how many more turns does it take to melt the solid bed if the channel depth is constant? Plot the solid bed profile X(z).

B. Plot the solid bed profile for the case where channel depth reduces from h to h/2 (compression ratio of 2) within the length predicted in part (A). Repeat for a compression ratio of 3.

D = screw diameter                                    45 mm

h = channel depth                                      4 mm

W = channel width                                      40 mm

n = screw rotational speed                          2 rev/s

m^· = mass throughput                                80 kg/s (Use to compute u_sz)

Use the following material properties:

Polyamide 66

ρ_s = density of the solid bed                   500 kg/m³

ρ_m = density of the polymer melt           1150 kg/m³

k_m = thermal conductivity of the melt     0.24 W/m/K

C_s = specific heat of the solid                 1670 J/kg/K

C_m =specific heat of the melt                 1300 J/kg/K

T_b = heater temperature od barrel          350^oC

T_m = melting temperature                      265^oC

T_s0 = initial temperature of solid             35^oC

λ = heat of fusion                                   205,000 J/kg

μ = viscosity                                          250 Pa-s

Solve the same problem as (A) with half the rotational speed and half the throughput.

Attachment:- Equations.rar