In this paper a hydrodynamic journal sliding bearing,forming with two nonparallel surfaces that the lower surface moves with a unidirectional velocity and the upper surface is stationary shaped with exponential geomet...In this paper a hydrodynamic journal sliding bearing,forming with two nonparallel surfaces that the lower surface moves with a unidirectional velocity and the upper surface is stationary shaped with exponential geometry is verified mathematically.The values of volumetric flow rate and distribution of pressure for incompressible lubricant flow between two supports in several conditions of velocity with different variables are determined.The results indicate that by increasing the amount of constant(m),the maximum oil pressure in the bearing will face an extreme decrease,and also by increasing theαcoefficient,the rate of volumetric flow rate will decrease.展开更多
A series of tests was conducted to unlock the potential application of MgO/water-EG(ethylene glycol)nanofluids(NF)in a double-pipe heat exchanger(HEX).The overall heat transfer coefficient(HTC),the inlet temperature o...A series of tests was conducted to unlock the potential application of MgO/water-EG(ethylene glycol)nanofluids(NF)in a double-pipe heat exchanger(HEX).The overall heat transfer coefficient(HTC),the inlet temperature of the working fluid,the fluid pressure drop(FPD),friction factor(FF)and the hydraulic performance index of the NF within the HEX were experimentally measured.Fouling of nanoparticles(NPs)within the Hex was also studied and modelled using asymptotic particulate fouling model.Results showed that MgO NPs can enhance the HTC by 39%at Re=10500 and wt.%=0.3 in the turbulent regime.Also,the presence of MgO NPs augmented the FF and the FPD values.The former was enhanced 33.8%,while the latter was augmented by 37%both at wt.%=0.3 and at Reynolds number=10500.Results also revealed that the formation of porous particulate fouling layer on the internal wall of the inner tube creates a fouling thermal resistance which changes asymptotically with time.Overall,MgO/water-ethylene glycol shows a great potential to be used as a coolant within a HEX.展开更多
文摘In this paper a hydrodynamic journal sliding bearing,forming with two nonparallel surfaces that the lower surface moves with a unidirectional velocity and the upper surface is stationary shaped with exponential geometry is verified mathematically.The values of volumetric flow rate and distribution of pressure for incompressible lubricant flow between two supports in several conditions of velocity with different variables are determined.The results indicate that by increasing the amount of constant(m),the maximum oil pressure in the bearing will face an extreme decrease,and also by increasing theαcoefficient,the rate of volumetric flow rate will decrease.
文摘A series of tests was conducted to unlock the potential application of MgO/water-EG(ethylene glycol)nanofluids(NF)in a double-pipe heat exchanger(HEX).The overall heat transfer coefficient(HTC),the inlet temperature of the working fluid,the fluid pressure drop(FPD),friction factor(FF)and the hydraulic performance index of the NF within the HEX were experimentally measured.Fouling of nanoparticles(NPs)within the Hex was also studied and modelled using asymptotic particulate fouling model.Results showed that MgO NPs can enhance the HTC by 39%at Re=10500 and wt.%=0.3 in the turbulent regime.Also,the presence of MgO NPs augmented the FF and the FPD values.The former was enhanced 33.8%,while the latter was augmented by 37%both at wt.%=0.3 and at Reynolds number=10500.Results also revealed that the formation of porous particulate fouling layer on the internal wall of the inner tube creates a fouling thermal resistance which changes asymptotically with time.Overall,MgO/water-ethylene glycol shows a great potential to be used as a coolant within a HEX.
