A series of chemical reactions happen in the coal gasifier and as a result, high temperature syngas is obtained which contains a lot of solid granules. The high-temperature syngas must be cooled, because it can not be...
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A series of chemical reactions happen in the coal gasifier and as a result, high temperature syngas is obtained which contains a lot of solid granules. The high-temperature syngas must be cooled, because it can not be utilized directly. The opposed water spray cooling is not only effective, but also could dedust the syngas. In the present study, the CFD technique is used to investigate the effect of the opposed spray cooling in a gasifier. The Euler-Lagrange method is applied to deal with the syngas and the water droplets respectively. A non-dimensional parameter Temperature Non-uniform Factor (TNF) is defined to confirm the height of the cooling section. The simulated results match the designed data well. If water droplets with small diameters are used, the single-stage water spray cooling is more economic than the two-stage water spray cooling.
Clogging failure is common for microfilter utilizing the flat membrane structure. To reduce clogging failure in microfilters, the turbine blade-like micropillar is introduced in microfilter design. Two improved cross-...
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Turbulent mixing layer flow with 200 mg/kg polymer additives was measured by PIV and compared with pure water cause. The velocity ratio between high and low speed is 4:1 and the velocity difference ranges from 0.25 m/...
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Turbulent mixing layer flow with 200 mg/kg polymer additives was measured by PIV and compared with pure water cause. The velocity ratio between high and low speed is 4:1 and the velocity difference ranges from 0.25 m/s to 1.25 m/s. It is showed that large vortex structures exist in flow field with/without polymer addictives, but the coherent structure is much clearer and the large eddy will roll up earlier when polymer is added. Similar with pure water case, the Reynolds stress is decreasing and the vorticity is increasing with increasing the velocity difference. However, the width and range of Reynolds shear stress and vorticity are wider and larger.
This paper presents a novel method to analyze the thermal conductance under vacuum environment for MEMS devices. The Si/Ge-based Pirani gauge introduced is developed for monitoring the package hermeticity of MEMS Bolo...
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An artificial neural network (ANN) for predicting Nusselt number was trained successfully based on the data of transition boiling experiment, which was conducted in confined space with downward facing surface at atmos...
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An artificial neural network (ANN) for predicting Nusselt number was trained successfully based on the data of transition boiling experiment, which was conducted in confined space with downward facing surface at atmospheric pressure. The effects of wall superheat, Δtw, the ratio of the gap size to the diameter of heated surface, δ/D, Prandtl number and Rayleigh number on Nusselt number under transition boiling condition were analyzed based on the trained ANN. A correlation used to accurately predict the natural convection heat transfer under the present condition was obtained and it provides a reasonable agreement against the experimental data.
In order to study the surface damage of solid material subjected to the high speed liquid impact, both numerical and experimental methods were established. The smoothed particle hydrodynamics and finite element analys...
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In order to study the surface damage of solid material subjected to the high speed liquid impact, both numerical and experimental methods were established. The smoothed particle hydrodynamics and finite element analysis were used to calculate the material damage. The conditions of PMMA and steel were analyzed to obtain the dynamic stress and strain distribution during impact. An experiment apparatus was build. The velocity of the impact jet was measured using a high speed camera and the apparatus. A digital microscope was used to measure the three dimensional profile of the sample before and after high speed liquid impact up to 600 m/s. The dimensions of damage area were recorded and analyzed statistically. Based on the statistical results, the performance of the materials resisting liquid corrosion was evaluated.
Based on the maximum CHF (critical heat flux) criterion, an optimal heat transfer criterion, which is called H criterion, was proposed. Experimental apparatuses were conducted. Distilled water was used as the working ...
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Based on the maximum CHF (critical heat flux) criterion, an optimal heat transfer criterion, which is called H criterion, was proposed. Experimental apparatuses were conducted. Distilled water was used as the working fluid. Three different DANFOSS nozzles with cone angles being 54deg, 50deg and 54deg respectively were used to cool a 30times30 mm 2 square copper surface. Experimental results indicated that the volumetric fluxes were pro-portioned to P 0.5 , where P is the pressure drop across the nozzles. The optimal distance between the nozzles and the heated surface were derived. The results indicated that the optimal heat transfer appeared while the outside of the impellent thin spray film inscribed in the square heated surface. Based on the H criterion aforementioned, two DANFOSS nozzles of the three were used to study the temperature distribution of the heated surface experimentally while there were spray inclination angles. Distilled water was also used impacting on the 30times30 mm 2 square copper surface aforementioned and a circular heated copper surface with diameters being 30 mm respectively. The heat flux of the surface was kept in constant (about 26-35 W/cm 2 ). The inclination angles were 0deg, 10deg, 20deg, 30deg, 40deg and 50deg respectively. Experimental results indicated that the grads of the temperature of the surface increases first and then decreases with the increase of the inclination angle.
Clogging failure is common for microfilter utilizing the flat membrane structure. To reduce clogging failure in microfilters, the turbine blade-like micropillar is introduced in microfilter design. Two improved cross-...
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Clogging failure is common for microfilter utilizing the flat membrane structure. To reduce clogging failure in microfilters, the turbine blade-like micropillar is introduced in microfilter design. Two improved cross-flow microfilter designs employing the blade-like micropillar barrier are presented, one with varied cross-section channels, and the other with Archimedes' spiral channels. Analogy experimental-data based simulations show that the two aforementioned novel microfilters have good filtrating efficiency and fantastic anti-clogging characteristics. And the commercial value of the turbine blade-like barriers is affirmed by the industry Partners.
The key reasons that the present method cannot be used to solve the industrial multi- phase flow pattern recognition are clarified firstly. The prerequisite to realize the online recognition is proposed and recognitio...
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The key reasons that the present method cannot be used to solve the industrial multi- phase flow pattern recognition are clarified firstly. The prerequisite to realize the online recognition is proposed and recognition rules for partial flow pattern are obtained based on the massive experimental data. The standard templates for every flow regime feature are calculated with self-organization cluster algorithm. The multi-sensor data fusion method is proposed to realize the online recognition of multiphaseflow regime with the pressure and differential pressure signals, which overcomes the severe influence of fluid flow velocity and the oil fraction on the recognition. The online recognition method is tested in the practice, which has less than 10 percent measurement error. The method takes advantages of high confidence, good fault tolerance and less requirement of single sensor performance.
In this paper the effect of velocity ratio on plane mixing layer was experimentally investigated by Particle Image Velocimetry (PIV). The velocity ratio between low and high speed side are 0.25 and 0.50, respectively....
In this paper the effect of velocity ratio on plane mixing layer was experimentally investigated by Particle Image Velocimetry (PIV). The velocity ratio between low and high speed side are 0.25 and 0.50, respectively. The Reynolds number based on the velocity difference of two streams and hydraulic diameter of the channel is 66000. The results indicate that the maximum mean Reynolds stress on the same cross section is decreasing with the velocity ratio increasing. The maximum dimensionless mean vorticity is decreasing according to an exponential law along the stream-wise direction and the decreasing speed of dimensionless mean maximum vorticity is increasing with the velocity ratio increasing. The dimensionless vorticity caused by plate wake is decreasing sharply in a very short distance along the down stream wise direction and the decreasing speed is faster when the velocity ratio is larger.
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