In this thesis, a calculation model is created to study a theoretical radiator-like configuration, consisting of a flat vertical plate heated with a constant capacity rate. This lumped capacitance model is partly created to more theoretically look at radiators with add-on-fans, but also to in such a setting look at fundamental heat transfer relationships. System heat transfer is studied for various heights, H (m), and freestream velocities, u (m/s). These results are then subject to validation, where comparison is made with values derived from two relevant reference studies. It is found that polynomial fits well describe the results obtained from calculation. The relationships for heat transfer Q (W), heat flux q (W/m2) thus become: π(π»,π’) = π00Β + π01π’ + π10π» + π11π»π’ + π02π’2Β (W) π(π»,π’) =π/π»= π00π»-1Β + π01π»-1π’ + π10Β + π11π’ + π02π»-1π’2Β (W/m2) For these relationships, polynomial coefficients π00, π01, π10, π11Β and π02Β are found for three temperature set-ups of system supply and return temperature at zero freestream velocity: 55/45, 45/35 and 35/25 (Β°C). These values are chosen as they correspond to standard temperatures for low-temperature heating set-ups. Model validation is successful for the case of natural convection (u = 0), whereas difficulties are encountered for the cases of mixed and forced convection. Reasons for these difficulties are discussed and it is concluded that there is a need for more experimental studies of flat vertical plates with non-isothermal wall temperature profiles.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-220138 |
| Date | January 2017 |
| Creators | Scheibe, Oskar |
| Publisher | KTH, StrΓΆmnings- och klimatteknik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-STKL ; 2017:02 |
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