Simulation Of Shock Losses At Shaft Bottom Junction In Mine Ventilation Systems Using Computational Fluid Dynamics And Scale Model Studies.: Shaft Bottom Junction In Mine Ventilation Systems Offers Complex Geometry, Leading To Large Scale Eddy Formations, And Is An Important Source Of Shock Loss On Account Of The Combined Effect Of Bend And Area Change. In Addition The Ventilation Energy Loss Is Expected To Be High On Account Of High Volume Flow Rates Through This Configuration. However, Mine Ventilation Literature Does Not Have Reference To The Shock Loss Factors At Shaft Bottom Junction. The Current Study Is Therefore Undertaken To Examine The Phenomenon Of Shock Loss At This Important Source. For This Purpose, Typical Shaft Bottom Geometry From An Underground Coal Mine Is Selected. Investigations Are Performed On Scale Models That Confirm To The Laws Of Dynamic And Geometric Similitude, And Also On The Real Life Scale Using Three Dimensional Cfd Simulations Using Fluent Software. The Effect Of Airway (Plat) Roughness And Also The Effect Of The Shaft Bottom Length On The Shock Loss Are Also Investigated, For Both Upcast And Downcast Shaft Bottom Junctions. The Plat Height, Width, And The Shaft Diameter Are Selected To Maintain Ratio Of 3:4:6 In The Study. The Shaft Bottom Length Is Varied In 0, 1, And 2 Times The Shaft Diameter. Roadway Roughness Is Varied From Smooth To A Relative Roughness (E/D) Value Of 0.112. Experiments Are Conducted By Fabricating The Setup Using Pvc Ducting And Plexiglas Sheet And By Using A Laboratory Scale Centrifugal Flow Fan. Airway Roughness Is Simulated By Pasting Thermocole Cubes Of Predetermined Size To The Inner Wall Of The Duct. Reynolds Number Ranging From 0.8x105 To 1.6x105 Is Created In The Experiments. Cfd Modeling Is Performed Using K-Ε Turbulent Model And ‘Quick’ Modules For Momentum And Turbulence Dissipation Rate And Energy. Boundary Conditions Are Such That At The Inlet Uniform Velocity Pressure Is Created And At The Outlet Static Pressure Is Taken To Be The Atmospheric Pressure. The Computed Total Pressure Values Along The Duct (Both In Case Of Cfd Simulations And Experiments) Are Plotted Along The Axial Length Of The Geometry, In Order To Establish The Abrupt Drop On Account Of Shock. The Drop Is Reported In Terms Of Shock Loss Factor By Normalizing The Total Pressure Drop With Respect To Velocity Pressure In The Shaft. The Studies Reveal That Airway Roughness Can Increase The Shock Loss Factors By 40% From A Smooth Surface To A Rough Surface (E/D = 0.112). Shaft Bottom Length Does Not Have An Appreciable Role In Contributing To The Shaft Bottom Shock Loss Factors. Good Agreement