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Öğe Impact of excess roughness on power consumption in pipe flows(Batman Üniversitesi, 2017) Düz, HasanIn this study, the effect of excess surface roughness on pump power consumption was investigated for water pipe flows. In fluid distribution systems, the impurities adhering to flow wall or the wall corrosion cause the flow surface being more roughly and as a consequent cause to more frictional drag. Here, an experimental study was carried out with water flows inside aluminium, copper, steel and galvanized pipes which are detached directly from the aging fluid distribution assemblings. Roughness heights of these dated pipes was measured by experimental way. The measured roughness heights were compared with new manufacture values, the dated pipes was found more roughly. An energy consumption analysis was carried out for one meter of pipe flow for the Reynolds number between 15000 < Re < 150000. Determinations showed that the friction existed due to excess surface roughness caused the pump power consumption to increase and cost also, especially at high Reynolds number about Re > 105Öğe Effects of thermal barrier coating on the performance and combustion characteristics of a diesel engine fueled with biodiesel produced from waste frying cottonseed oil and ultra-low sulfur diesel(Taylor & Francis, 2016-09-01) Aydın, Selman; Sayın, Cenk; Altun, Şehmus; Aydın, HüseyinIn this study, the top surfaces of piston and valves of a four-strokes and direct-injection diesel engine have been coated—with no change in the compression ratio—with a 100 μm of NiCrAl lining layer via plasma spray method and this layer has later been coated with main coating material with a mixture of 88% of ZrO 2 , 4% of MgO and 8% of Al 2 O 3 (400 μm). Then, after the engine-coating process, ultra-low sulfur diesel (ULSD) as base fuels and its blend with used frying cottonseed oil derived biodiesel in proportion of 20%, volumetrically, have been tested in the coated engine and data of combustion and performance characteristics on full load and at different speeds have been noted. The results, which were compared with those obtained by uncoated-engine operation, showed that thermal efficiency increased, and engine noise reduced. Cylinder gas pressure values obtained from the diesel engine which has been coated with thermal barriers have been found to be somewhat higher than those of the uncoated-engine. Also, maximum pressure values measured in both engines and under the same experimental conditions through the use of test fuel have been obtained after TDC. Moreover, heat release rate and heat release have occurred earlier in the coated-engine. NOx emissions were increased while CO and HC emissions were remained almost the same with a little bit decrease.
