Modification of a radial fan for use in a tumble dryer

Delovanje sušilnih strojev temelji na principu vpihovanja segretega zraka v boben, kjer poteka proces izparevanja vode iz oblačil. Za vpihovanje oziroma pogon zraka po sistemu skrbi radialni ventilator z naprej zavitimi lopaticami, za katerega je značilna položna karakteristika z izrazitim nestabilnim delom. Z meritvijo aerodinamskih lastnosti sta bila določena delovna karakteristika obravnavanega ventilatorja in obratovanje v nestabilnem področju karakteristike. Na podlagi tega smo z namenom delovanja v stabilnem področju računsko analizirali vpliv vrtilne frekvence, premera in višine ventilatorja na delovno karakteristiko. Izbrana je bila najugodnejša kombinacija zgoraj navedenih parametrov, ki je temeljila na geometrijski prilagoditvi ventilatorja. Sledili sta izdelava in vgradnja prilagojenega ventilatorja v sušilni stroj, na katerem smo opravili meritve aerodinamskih lastnosti. S temi smo potrdili uspešnost računskega dela prilagoditve ventilatorja. Pri izbrani masi polnitve perila smo opravili funkcionalne teste, pri katerih se je izkazalo, da smo s prilagoditvijo ventilatorja dosegli za 8 % krajši čas cikla sušenja ob 2-odstotnem znižanju porabljene električne energije. Prav tako so bile izmerjene nižje vrednosti fluktuacij tlaka in pretoka.Tumble dryer works on principle of drawing in air through vents which is then heated and distributed throughout the drum to draw moisture from clothing. The air is blown and recirculated throughout the system by a forward curved radial fan which has a flat characteristic curve with distinct volatile area which has a negative impact on drying process. Measurements of aerodynamic properties defined the operation characteristic of the named fan and the operation characteristics in the volatile area. With intentions of running the equipment at the stable part of the curve we mathematically analyzed the effect of spinning frequency, diameter and fan height on operating characteristics. The most suitable combination from the previously listed parameters was chosen, which was based on geometrical adjustment of the fan. After that followed the manufacturing and installation of the adjusted fan on which we made aerodynamic characteristics measurement. Results of the mathematical analysis confirmed successful calculation of the adjusted fan. With the adjusted fan and the chosen mass of laundry we executed functionality tests of which the results showed 8 percent shorter drying cycles, power consumption dropped by 2 percent and lower values of pressure fluctuation were noticed