| Revista: | Journal of the Brazilian Society of Mechanical Sciences and Engineering |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000312286 |
| ISSN: | 1678-5878 |
| Autores: | Auracher, H1 Buchholz, M2 |
| Instituciones: | 1Technical University of Berlin, Berlín. Alemania 2Robert Bosch GmbH, Stuttgart, Baden-Wurttemburg. Alemania |
| Año: | 2005 |
| Periodo: | Ene-Mar |
| Volumen: | 27 |
| Número: | 1 |
| Paginación: | 1-22 |
| País: | Brasil |
| Idioma: | Inglés |
| Tipo de documento: | Artículo |
| Enfoque: | Experimental |
| Resumen en inglés | The lecture presents a survey of results found by the author and his team during recent years. An experimental technique for precise and systematic measurements of entire boiling curves under steady-state and transient conditions has been developed. Pool boiling experiments for well wettingfluids and fluids with a larger contact angle (FC-72, isopropanol, water) yield single and reproducible boiling curves if the system is clean. However, even minimal deposits on the surface change the heat transfer characteristic and shift the boiling curve with each test run. The situation is different under transient conditions: heating and cooling transiens yield different curves even on clean surfaces. Measurements with microsensors give an insight in the two-phase dynamics above the heating surface and the temperature field dynamics above and beneath the surface. Microthermocouples (38 µm diameter) enbedded in the heater (distance to the surface 3.6 µm), a micro optical probe (tip diameter ~ 1.5 µm) and a microthermocouple probe (tip diameter ~ 16 µm), both moveable above the heater surface, are used for these studies. In nucleate boiling, very localized and rapid temperature drops are observed indicating high heat fluxes at the bottom of the bubbles. Already before reaching the critical heat flux (CHF), hot spots occur the size of which increases towards the Leidenfrost point. In the entire transition boiling regime wetting events are observed, but no ones in film boiling. In low heat flux nucleate boi |
| Disciplinas: | Ingeniería |
| Palabras clave: | Ingeniería industrial, Ebullición, Transferencia de calor, Calentadores |
| Keyword: | Engineering, Industrial engineering, Boiling, Heat transfer, Heaters |
| Texto completo: | Texto completo (Ver PDF) |
