1 / 30

Environmentally Conscious Design & Manufacturing

Environmentally Conscious Design & Manufacturing. Class 11: Air Quality 2. Prof. S. M. Pandit. Agenda. Mist models - Introduction Predicting cutting fluid mist Experiment Atmospheric aerosols. Introduction. Sources Cutting fluid Condensation Atomization / Condensation

august
Download Presentation

Environmentally Conscious Design & Manufacturing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Environmentally Conscious Design & Manufacturing Class11: Air Quality 2 Prof. S. M. Pandit

  2. Agenda • Mist models - Introduction • Predicting cutting fluid mist • Experiment • Atmospheric aerosols

  3. Introduction • Sources • Cutting fluid • Condensation • Atomization / Condensation • Splashing & Drag out processes • Atmospheric

  4. Condensation - 1 • Heat generated in the workzone may result in cutting fluid jet boiling and evaporation.

  5. Condensation - 2 • Estimate evaporation rate through the heat flux prediction. • Analytical Techniques • Closed form solutions of temperature distributions (temporal & spatial) due to conduction and convection with a moving heat source • Experimental validation

  6. Atomization - 1 Motivation • Relationship between drop size and droplet suspension • drop size distribution • deposition in the various regions of the human respiratory tract.

  7. Atomization - 2 • Fluid jet impinging a stationary flat plate • Boundary layer • Splatter

  8. Atomization - 3 Modes of liquid film disintegration: • Drop formation mode • Ligament formation mode • Splatter

  9. Atomization - 4 - Rotating Workpiece: Wave development followed by drop separation s-surface tension force

  10. Splashing & Dragout • Splashing • Dragout • Ligament formation • Breakup modeling • Force balance

  11. Mist Control Strategies • Enclosing the machine tool • - restrict to access to the machine tool • Using air filters and mist collectors • - expensive to maintain and operate • Adding antimisting agents to cutting fluid • - be effective in suppressing mist formation • - added cost

  12. Experimental Investigation • Purpose: • Examine the underlying process conditions that • affect the mass concentration level of cutting fluid mist • Identify significant factors to lead to modifications in the • machining process as an alternative solution for • minimizing cutting fluid mist • Underlying process: • Turning

  13. Experiment Setup Lathe: Emco Compact Nozzle sizes: 0.3175 cm and 0.635 cm Fluid flow rate: 3.4 l/min Mass concentration measurement: Aerosol monitor

  14. PM10 Experiment Design • Two level fractional factorial design • Investigated variables: • Spindle speed • Workpiece diameter • Nozzle diameter • Cutting fluid oil concentration • Sampling locations (X, Z)

  15. Variable Levels for PM10 Experiment

  16. Sampling Probe Location

  17. Mass Concentration Measurement

  18. PM10 Experiment Analysis • Significant effects: • Spindle speed • - Increase speed produces a mechanical energy • and Lead to the formation of droplets. • Workpiece diameter • - A large diameter results in a great surface velocity • X-location

  19. Variable Levels for PM2.5 Experiment

  20. PM2.5 Experiment Analysis • Significant effects: only spindle speed • Fine particles are uniformly distributed in • the air around the machine tool. • A larger workpiece diameter results in more • coarse particles, but has little effect on the • number of fine particles.

  21. Summary of Experiments • Spindle speed is the most significant variable affecting • PM10 and PM2.5 mass concentration. • Workpiece diameter has a significant effect on PM 10 but • not on PM2.5 mass concentration. • X-location is significant for PM10 but not for PM2.5 mass • concentration. • Attention should be focused on high speed machining • operation (turning, face milling, and boring)

  22. Relevance in manufacturing Characterization Atmospheric Aerosols

  23. Atmospheric Aerosols - 1 • Aerosols impact the chemistry and physical processes of the troposphere in several ways: • Cloud condensation nuclei (CCN), they directly impact the earth's radiative budget via light scattering • Serve as sites for heterogeneous reactions.

  24. Atmospheric Aerosols - 2 Aerosol > 1microns serve as ice nuclei, and may contain the bulk of the aerosol mass; Submicron aerosol become CCN in the ambient atmosphere and are efficient light-scatterers.

  25. Atmospheric Aerosols - 3 • Need - Composition of aerosols as a function of size • Measurement of sulfate and soluble organics as a function of aerosol size • Example: • Quantify the fate of emitted anthropogenic and biogenic sulfur compounds

  26. Aerosol Chemistry • Heterogeneous interaction of gaseous molecules with aerosol particle surfaces • Characterization of atmospheric aerosols, mainly in the free troposphere.

  27. NOAA

  28. What happens? • Radiation scattering • Natural • Human activity (industry) • Sulfur emissions from various sources Re. National Oceanic and Atmospheric Administration

  29. Global Sulfur Emissions

More Related