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Gas Dynamics of Flow through Valves

This resource explores the gas dynamics of flow through valves, including the estimation of flow capacity and the effects of valve passage geometry. It covers topics such as stream tube formation, nozzle configurations, governing equations, and the nature of real flow. The resource also discusses the specific mass flow rate, conditions for choked flow, and the extent of valve opening. Additionally, it incorporates the effects of friction and compressible flow in both inlet and exhaust valves.

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Gas Dynamics of Flow through Valves

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  1. Gas Dynamics of Flow through Valves P M V Subbarao Professor Mechanical Engineering Department Method to Estimate the Flow Capacity of Valve Passage….

  2. Stream Tube formed by Flow Through Valves Equivalent Converging-Diverging Nozzle Configurations: Mild Separation. Severe Separation

  3. Models for Valve Flow Passage Instantaneous Minimum Area

  4. Instantaneous Governing Equations Non reacting, no body forces, viscous work negligible Conservation of momentum for frictional steady flow: Conservation of energy for ideal steady flow:

  5. Ideal Gas law : Mach number equation :

  6. Nature of Real Flow : Variable Area Ducts

  7. Compressible Real Flow Effect of Mach number is negligible on friction factor….

  8. Friction Factor for Compressible Flow Laminar Flow Turbulent Flows k : Roughness Parameter

  9. Mach Models for Isentropic Valve Flow Passage Minimum Area Effect of Differential Change in Area:

  10. Specific Mass flow Rate through Valve Passage Mass flow rate per unit area of cross section:

  11. Conditions for Choked Flow

  12. Isentropic Compressible Flow Through Inlet Valve Resource : The total pressure in the inlet manifold – Cylinder pressure • The air flow rate is related to the upstream stagnation pressure p0 and stagnation temperature T0, Static pressure just down stream of the valve and a reference area AR. • AR is a characteristic of the valve design. When the flow is chocked:

  13. Isentropic Compressible Flow Through Exhaust Valve Resource : The total pressure in the cylinder – Static Pressure in Exhaust manifold • The gas flow rate is related to the cylinder stagnation pressure p0,cyl and stagnation temperature T0,cyl , Static pressure just down stream of the valve and a reference area AR. • AR is a characteristic of the valve design. When the flow is chocked:

  14. Early Choking of Valve Passage Extent of Valve Opening

  15. Frictional Compressible Flow Through Inlet Valve • The real gas flow effects are included by means of an experimentally determined discharge coefficient CD. When the flow is chocked:

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