Hydrodynamics And Heat Transfer Characteristics Of Draft Tube Spouted Bed Roasting Of Groundnuts (Arachis Hypogeae)
V.D. Nagaraju, B.S. Sridhar
Key Words: Spouted bed; Hydrodynamic; Draft Tube; Roasting; Groundnut
Abstract: The hydrodynamic characteristics of flow regime were studied employing different draft tubes during the spouted bed roasting of groundnuts and the dimensionless parameters were employed for predicting the flow regime. The estimated Reynolds's number (Re) under the turbulent convection regime was ≈ 8399. The size of the draft tubes employed ranged from 0.175 to 0.375 m length and 0.065 m diameter. The optimal processing condition was found to be the draft tube size of 0.275 m length with heat transfer coefficient of 132 W/m2-C. The studies showed that draft tube insertion is a versatile technique to increase the bed height as compared to the classical spouted bed roaster and can be seen as a promising roaster design for groundnuts and related heat sensitive particulate materials that have slow intra -particle heat transfer coefficients.
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