Advanced Materials Research Vols. 550-553

Abstract: Good mixing in fluids is an important factor that ensures efficient reactions as well as effective heat and mass transfer operations. The mixing behavior of fluids in micro channels has been assessed using identification numbers to characterize flow regimes as, laminar, vortex and engulfment. To demonstrate this, the hydrolysis of ethyl acetate with potassium hydroxide was studied in three different sized micro channels of diameters 0.27, 0.53 and 0.86 mm. The identification numbers obtained from the hydro dynamics within these channels have been compared with the improved performance in these micro channels, based on percentage conversion of the hydrolysis reaction. In this study the identification numbers ranged from 5 to 23. The performance as percentage conversion was better in the smaller diameter channel where the identification number was higher and was found to be lower in the larger diameter channel where the identification number was lower.

Abstract: The objective of this research was to study the effects of types of drum, clearances (CR) and drum speeds on performance of job’s tears shelling unit. The types of drum were peg tooth and rasp bar with an open shelling drum. Clearances of 10, 15 and 20 mm were tested with the drum speeds of 350, 400, 450 and 500 rpm. The results found that the rasp bar drum with 10 mm of clearance and 400 rpm of drum speed were suitable condition for shelling with capacity of 12.98 kg/h and efficiency of 99.76 % which provided 71.65% of whole and small damage kernels (% FK + % KQ).

Abstract: In this article, simulation analysis has been performed for the flow and heat transfer performance of spiral flow double-pipe heat exchanger using finite volume method, respectively for the relationship between Nu and the average shear force on inner pipe outer wall at different turbulent flow Re with different radial offset of inlet and outlet pipes and different spacing of inlet and outlet pipes. The results show that, as compared with an ordinary double-pipe heat exchanger, in a spiral flow double-pipe heat exchanger, both inner pipe convective heat exchange coefficient and inner pipe wall surface shear force are lower, with the magnitude of reduction related to a number of factors such as radial offset of inlet and outlet pipes and Re. The study in this article has provided theoretical basis for further engineering application of spiral flow double-pipe heat exchangers.

Abstract: The mechanical and structure designs are carried out in this paper for Sieve-tray tower used in chemical unit operations. Through the use of SW6 soft based on GB150, JB4710,the thickness of the equipment determined and the calculating for load, bending, axial stress are dealt. The strength and stable are checked for every dangerous section. For inner components of tower structure designs are carried out, assembly drawings and parts drawings are given according to the designed results.

Abstract: According to GB151 and GB150, the process design and structure design have been done for the floating head heat exchanger which is common in the chemical unit operation equipment. The software SW6 is used to compute the wall thickness, loading and etc. Strength design and structure design of the Tube-sheets, Tube-Chambers and Supports have also been finished on SW6. The results show that the equipment can meet the required strength.

Abstract: The flow fields of the flocculators with different baffle which shape is vertical, perforated, arc and sine respectively were numerically simulated. The simulation parameters such as velocity, turbulent intensity, shaft power were compared in different types of baffled reactor. It shows that the calculated flow field matched the experiment results. Compared with the vertical baffles, the other three baffles such as perforated, arc and sine baffles, in varying degrees increased the average velocity and turbulence, and reduce energy consumption, in which the enhancement effects of sine baffles on flow field were especially prominent. In the sine baffled flocculator the average velocity and turbulent intensity was raised 2.6% and 3.8% respectively, and the shaft power was saved 5.78%. Reasonable structure of baffles can effectively resolve the problem of non-homogeneous mixture, intensify the flow field of flocculation reaction, improve flocculating effect, and reduce energy consumption.

Abstract: Bernoulli equation is used in this paper to deduce the calculation formula for the height of liquid seal in the U shape tube. Practice shows the result is reasonable and right.The conclusions provide foundation for engineering design.

Abstract: Spouted bed with porous draft tube is an improved type of conventional spouted bed which is a special kind of fluidized bed. Hydrodynamic characteristics are vital to design and normal operating of spouted bed with porous draft tube, but less research has been carried out. Two key hydrodynamics factors including maximum spouted bed height and minimum spouting velocity were studied by a series of experiments. The effects and mechanisms of features of draft tube including diameter, installing position and hole opening ratio on hydrodynamics factors were analyzed. The results are of great value to the design and optimization of spouted bed with porous draft tube and broad the engineering application sphere of spouted bed.

Abstract: Mounting headstock is an important part of the vegetable transplanting machine, its strength directly affects the machine's performance. The modal analysis of three types of headstocks while lifting and lowering implement were carried out with ANSYS finite element analysis software, the natural vibration characteristics including natural frequency, damping ratio and modal vibration mode of each particular mode without external interference were obtained, The comparison among the three structures was conducted and it may provide a theoretical basis for the structure design of the mounting headstock of vegetable transplanting machine .

Abstract: The purpose of this resarch was investigated the air-oil temperature field distribution under air-oil lubrication and oil lublubrication, meanwhile also study the air-oil lubrication effect under different air velocity inlet the bearing cavities of the high-speed paper machine dryer section. Base on the CFD theory, the temperature field of CARB bearing outer ring and the velocity field of the bearing cavities were simulated by the FLUENT software.Result show that air-oil lubricatin can reach the same cooling effect is contras with oil lubrication in the same heat production by roller; the best air-velocity value of air-oil lubrication system is obtain for the change of temperature and pressure in bearing cavities. It is confirm that the air-oil lubrication is viable in the high-speed paper machine dryer section.