Numerical And Experimental Investigation Of The Performance Of An Improved Conical Spouted Bed Coffee Roaster

Abstract

Obtaining High-Quality Coffee Depends On The Roasting Process. The Quality Parameter Like Bean Temperature Is One Of The Most Important And Difficult Physical Changes In Roasting. This Implies Controlling The Roasting Time, Temperature, And Geometry Of The Contactor Such That Achieving A Uniform And Efficient Heat Transfer Rate, Without Affecting The Aroma And Flavor Of Coffee Beans Could Be Adapted. Hence, This Paper Is Aimed To Improve The Performance Of Conventional Spouted Beds Based On The Combined Approach Of Computational Fluid Dynamics (Cfd) And The Discrete Element Method (Dem), And Also The Full-Scale And Operating Prototype Is Fabricated For An Experimental Investigation To Validate The Numerical Results. Based On The Analysis Results Obtained From The Existing Model, A Device Useful As Batch Type Conical Spouted Bed With An Internal Device (Csbwid) Like Fountain Confiner And Open-Sided Draft Tube For Roasting One Kilogram Of Coffee Beans Estimated To 6030 Number Of Particles With A Static Bed Height Of 0.20mIs Designed, Developed And Analyzed Using The Same Approach To Study And Improving The Thermo-Hydrodynamic Parameter. Engineering Software Like That Of Ansys Space Claim Was Used For 3d Modeling, Cfd Fluent, And Rocky Dem For Simulation And Dem Analysis. The Result Of The Simulation Indicates That The Coffee Bean Temperature Increases With The Increment Of Air Inlet Temperature And Time. Therefore, The Variation In The Particle Temperature With A Conical Spouted Bed With An Internal Device For The Operating Air Temperature Of 250??? Specifies That Coffee Beans Increase To A Very High Level (More Than "500k"), While In A Conventional Spouted Bed, Particle Temperatures Are Found To Be Lower (Around "470k"). The Convective Heat Transfer Coefficient Instantaneously Increases With Coffee Beans Temperature Distribution, Which Is The Most Important Factor That Enhances The Heat Transfer Rate During Coffee Bean Roasting. The Estimated Heat Transfer Coefficients For Coffee Bean Using A Conventional Spouted Bed (Existing) Which Was Found To Be 31 W/, Whereas It Is Increased To About 77.5 W/ For An Improved Conical Spouted Bed With An Internal Device. To Achieve The Spouting Phenomenon For The Required Capacity Of A Conical Spouted Bed, The Blower Was Selected As Capable Of Handling 250Cfm Of The Mass Flow Rate Of Air, And An Air Heater For Maintaining The Required Temperature Of Coffee Roasting From 190-250??? Is Selected With The Power Consumption Of An 18kw Wattage Requirement. The Analysis Of Variance Reveals That The Air Speed Accounts For The Largest %Contribution Of About 60.90% Which Is A Most Significant Factor, While The Mass Of Coffee Beans Is About 36.45% Which Is The Next Significant Factor In The Performance Of The Roasting Machine. Generally, The Results Are Predicted By The Numerical Method Are Approximately Near To The Result That Is Experimentally Obtained.