Turbulent drag reducing characteristics of CTAC/NaSal aqueous solution (CTAC had same mass concentration with NaSal.) were investigated in a two-dimensional channel of 30 mm height and 375 mm width, which was made of ...
详细信息
Turbulent drag reducing characteristics of CTAC/NaSal aqueous solution (CTAC had same mass concentration with NaSal.) were investigated in a two-dimensional channel of 30 mm height and 375 mm width, which was made of transparent acrylic resin. The measured drag reduction data were scaled up by using Hoyt's scaling method and were compared with other reported drag reduction data for different channel sizes. It could be concluded that both the critical temperature and critical Reynolds number at which turbulent drag reduction of surfactant solution occurred increased with concentration. There was a maximum drag-reduction about 60% for the measured CTAC/NaSal solutions. The Hoyt's scale-up method correlated well the experimental data for different channel heights when the SIS (shearing induced structure) was established very well in surfactant solutions.
The evolution and coverage of bubbles resulting from gas evolution at the reaction interface significantly impact mass transfer and the flow field within the photoelectrochemical water splitting system, posing a signi...
详细信息
The evolution and coverage of bubbles resulting from gas evolution at the reaction interface significantly impact mass transfer and the flow field within the photoelectrochemical water splitting system, posing a significant obstacle to overcoming the efficiency bottleneck of photoelectrochemical water splitting. In situ bubble observation can be realized via a coupled experimental system combining electrochemical measurements and high-speed imaging. The results indicate that bubble growth behavior correlates with system temperature and operating voltage; that is, the bubbles grow in an oscillating state on the electrode surface at the low operating voltage and high system temperature. Besides, the deviation amplitude of oscillating bubbles increases with system temperature yet decreases with operating voltage. The results indicate that the time coefficient of the growing bubble decreases, while the growth rate and gas evolution efficiency of the bubble increase with the increase of oscillating amplitude in the horizontal direction. The study of dynamic behaviors between the oscillating bubble and the contacted electrode reveals that the bubble oscillation is characterized by the periodic contraction and extension of the triple line. The mass transfer model of concentration boundary layer and the force model of oscillating bubble are constructed based on the interaction between the bubbles and the surrounding flow field. The mass transfer model has considered the microconvection caused by single-phase natural convection, gas-liquid interface expansion, and the oscillation of bubbles. Then through the force balance model, the solutal Marangoni force is found to gradually increase as the contact line extends outward.
This paper presents some initial results on the separate effects of shear and compositional inhomogeneities on the global structure of turbulent lean piloted premixed flames. Shear is introduced by injecting the mixtu...
详细信息
Post combustion systems (PCS) are a viable technology option to reduce carbon dioxide in the electricity production. However, the energy-intensive of PCC precludes its wide scale application. As for the optimization o...
详细信息
Combustion characteristics of diluted hydrogen-air premixed combustion were studied in a constant volume bomb over wide ranges of diluent ratios and equivalence ratios using two kinds of diluent gases. A two-zone mode...
详细信息
In this study, a coarse-grained molecular dynamic simulation was employed to test the influence of salts in morphology of structures in surfactant-polymer solutions. The surfactant was cetyltrimethyl ammonium chloride...
详细信息
In the petroleum refining industry, the fossil fuel used by the atmospheric and vacuum distillation units takes large proportion to the plant-self energy consumption. It is necessary to optimize the system for the ene...
详细信息
In the petroleum refining industry, the fossil fuel used by the atmospheric and vacuum distillation units takes large proportion to the plant-self energy consumption. It is necessary to optimize the system for the energysaving consideration. In this study, the exergy analysis method was utilized to optimize the gas collecting system. It is found that, the water bath furnace was a weak link, so we must improve inlet temperature of the fuel and reduce the number of excess air to enhance the economy of the system and reduce the exergy loss.
The performance of 3 types of energy utilization cycles including the organic Rankine cycle, the single stage static hydrogen compression cycle, and the new multistage continuous hydrogen compression cycle were analyz...
详细信息
The nozzle exit position (NXP) is a significant parameter for an ejector. In this work, a two dimensional (2D) homogeneous CFD model is developed to simulate the two-phase ejector used in transcritical CO2 refrigerati...
详细信息
ISBN:
(纸本)9782362150128
The nozzle exit position (NXP) is a significant parameter for an ejector. In this work, a two dimensional (2D) homogeneous CFD model is developed to simulate the two-phase ejector used in transcritical CO2 refrigeration cycle and NXP is focused on. After model validation, the flow fields in ejectors with different NXPs are simulated and an optimal NXP is obtained. According to the numerical results, with the increase of the NXP, a higher velocity and lower pressure are achieved for the primary fluid in the suction chamber which enhances the entrainment of the secondary fluid. Oppositely, the flow area of the primary fluid at the mixer inlet increases with the NXP which reduces the secondary flow rate. A compromise between these two factors leads to the optimal NXP with the highest entrainment ratio under the same operating condition. The results are helpful to the optimal design and control of the ejector.
The hot corrosion tests of the austenitic TP347HFG in molten sulfates with and without external stresses were conducted at 700 and 750 oC. The corroded specimens of different conditions were investigated through measu...
详细信息
暂无评论