Design, analysis and optimization of nozzles in a washing machine

Date

2023-4

Author

Çil, Mert

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One of the most important issues in the washing machine is to provide a better washing performance with low energy consumption. In order to achieve better washing performance at low energy consumption, the stain needs to be removed quickly. Removal of the stain is increased through the circulation of the water and the directing of the water with the nozzle. With the existing nozzle designs, an additional part is required to spray water over a wider area, however with the new nozzle designs presented in this thesis, it is possible to spray water directly over a wider area. Fluidic oscillator nozzles are used in many industries, and this thesis examines of stain removal with these nozzles. For the design parameters, the ratios of the critical widths in the nozzle structure to the nozzle inlet width were studied. In order to understand the effect of the parameters on stain removal, analyzes were performed with Computational Fluid Dynamics (CFD) and velocity graphs at the nozzle outlet were investigated. An approximation method was determined to model the stain removal effect using the graph of the average velocity for one full sweep of the nozzles. For validation of the determined approach, nozzles with different flow movements of three different parameters were determined, then results of the numerical analyses and experimental tests were compared. These parameters were determined as the ratio of the inlet of the nozzle mixing chamber to the nozzle inlet w1/w0, the ratio of the mixing chamber width to the nozzle inlet w2/w0 and the ratio of the nozzle outlet throat to the nozzle inlet w3/w0, respectively. The ratios of the reference nozzle were defined as w1/w0 = 2.0, w2/w0 = 4.06 and w3/w0 = 1.3. In order investigate the difference in flow analysis for the first parameter w1/w0, in addition to the reference ratio, ratios of 1.0 and 1.5 were also examined. In addition to the reference condition, the ratios of 3.2 and 4.8 were determined for the second parameter. As the final validation parameter, the ratios of 1.6 and 2.0 for w3/w0 were examined alongside the reference condition. The behavior of the stain removal curves is modeled using the nozzle output velocity graph obtained as a result of all validation tests. According to the determined model, the best ratios for w1/w0, w2/w0 and w3/w0 parameters were determined as 2.0, 5.02 and 0.75, respectively, using CFD analysis. Experimental studies were carried out for three different nozzles by changing only the specified parameter while keeping all other parameters constant. In addition, as a new parameter, the ratio of the backflow channels to the nozzle inlet w4/w0 was examined. CFD analyzes were performed with the determined model for w4/w0 and although w4/w0 = 1.47 was selected in the reference nozzle, the best nozzle design was determined as w4/w0 = 2.0 within the structural limits. It is seen that the experimental test results in all of the select ed nozzles are consistent with the determined method.

Subject Keywords

Washing machine, Nozzle design, Fluidic oscillator, Computational fluid dynamics, Stain removal

URI

https://hdl.handle.net/11511/103194

Collections

Graduate School of Natural and Applied Sciences, Thesis