Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids
This study explores the optimisation of nozzle design for external twin fluid, single-stage atomisation in handling high-viscosity, shear-thinning polydimethylsiloxane (PDMS). A single PDMS grade was employed and atomised using unheated sonic air and the viscosity was varied by the fluid temperature...
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2025-07-01
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| author | Marvin Diamantopoulos Christoph Hochenauer |
| author_facet | Marvin Diamantopoulos Christoph Hochenauer |
| author_sort | Marvin Diamantopoulos |
| collection | DOAJ |
| description | This study explores the optimisation of nozzle design for external twin fluid, single-stage atomisation in handling high-viscosity, shear-thinning polydimethylsiloxane (PDMS). A single PDMS grade was employed and atomised using unheated sonic air and the viscosity was varied by the fluid temperature. A systematic experimental approach was used, varying nozzle geometry—specifically apex angle, gas nozzle diameter, and number of gas nozzles—to identify the optimal nozzle configuration (ONC). The spray qualities of the nozzle configurations were evaluated via high-speed imaging at 75,000 FPS. Shadowgraphy was employed for the optical characterisation of the spray, determining the optimal volumetric air-to-liquid ratio (ALR), a key parameter influencing energy efficiency and operational cost, and for assessing droplet size distributions under varying ALR and viscosity of PDMS. The ONC yielded a Sauter mean diameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>d</mi><mn>32</mn></msub></semantics></math></inline-formula> of 570 × 10<sup>−6</sup><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">m</mi></semantics></math></inline-formula>, at an ALR of 8532 and a zero-shear viscosity of 15.9 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>Pa</mi></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">s</mi></semantics></math></inline-formula>. The results are relevant for researchers and engineers developing twin fluid atomisation systems for challenging industrial fluids with similar physical properties, such as those in wastewater treatment and coal–water slurry atomisation (CWS). This study provides design guidelines for external twin fluid atomisers to enhance atomisation efficiency under such conditions. |
| format | Article |
| id | doaj-art-05720c581a7c4fe985679dc9a024b785 |
| institution | DOAJ |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj-art-05720c581a7c4fe985679dc9a024b7852025-08-20T02:45:53ZengMDPI AGApplied Sciences2076-34172025-07-011514799210.3390/app15147992Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning FluidsMarvin Diamantopoulos0Christoph Hochenauer1Insitute of Thermal Engineering, Graz University of Technology, Inffeldgasse 25B, 8010 Graz, AustriaInsitute of Thermal Engineering, Graz University of Technology, Inffeldgasse 25B, 8010 Graz, AustriaThis study explores the optimisation of nozzle design for external twin fluid, single-stage atomisation in handling high-viscosity, shear-thinning polydimethylsiloxane (PDMS). A single PDMS grade was employed and atomised using unheated sonic air and the viscosity was varied by the fluid temperature. A systematic experimental approach was used, varying nozzle geometry—specifically apex angle, gas nozzle diameter, and number of gas nozzles—to identify the optimal nozzle configuration (ONC). The spray qualities of the nozzle configurations were evaluated via high-speed imaging at 75,000 FPS. Shadowgraphy was employed for the optical characterisation of the spray, determining the optimal volumetric air-to-liquid ratio (ALR), a key parameter influencing energy efficiency and operational cost, and for assessing droplet size distributions under varying ALR and viscosity of PDMS. The ONC yielded a Sauter mean diameter <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>d</mi><mn>32</mn></msub></semantics></math></inline-formula> of 570 × 10<sup>−6</sup><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">m</mi></semantics></math></inline-formula>, at an ALR of 8532 and a zero-shear viscosity of 15.9 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>Pa</mi></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">s</mi></semantics></math></inline-formula>. The results are relevant for researchers and engineers developing twin fluid atomisation systems for challenging industrial fluids with similar physical properties, such as those in wastewater treatment and coal–water slurry atomisation (CWS). This study provides design guidelines for external twin fluid atomisers to enhance atomisation efficiency under such conditions.https://www.mdpi.com/2076-3417/15/14/7992twin fluid atomisationhigh-viscositypolydimethylsiloxaneatomiser design |
| spellingShingle | Marvin Diamantopoulos Christoph Hochenauer Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids Applied Sciences twin fluid atomisation high-viscosity polydimethylsiloxane atomiser design |
| title | Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids |
| title_full | Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids |
| title_fullStr | Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids |
| title_full_unstemmed | Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids |
| title_short | Optimised Twin Fluid Atomiser Design for High-Viscosity, Shear-Thinning Fluids |
| title_sort | optimised twin fluid atomiser design for high viscosity shear thinning fluids |
| topic | twin fluid atomisation high-viscosity polydimethylsiloxane atomiser design |
| url | https://www.mdpi.com/2076-3417/15/14/7992 |
| work_keys_str_mv | AT marvindiamantopoulos optimisedtwinfluidatomiserdesignforhighviscosityshearthinningfluids AT christophhochenauer optimisedtwinfluidatomiserdesignforhighviscosityshearthinningfluids |