Applied Mechanics and Materials Vols. 130-134

Abstract: For solving cleaning fouling online for shell-and-tube heat exchanger，an asymmetric spiral-gear cleaning technology is presented. The RNG k-ε turbulent model is used to simulate the fluid flow and heat transfer of the tube with the spiral-gear. Its velocity and turbulent intensity field, convection heat transfer characteristic and resistance property are analyzed. Numerical simulation results shows that radial velocity is larger in the annular area near the tube wall than that in the smooth tube. Tangential velocity in the diameter area corresponding to the width of spiral-gear insertion increases with radius，but it decreases with radius in the annular clearance between the insert and the tube wall. However, fluid tangential motion of the smooth tube is only stochastic，and its tangential velocity is lower several orders of magnitude than that for the tube with the insertions. The average surface heat transfer coefficient of the spiral-gear-inserted tube wall is increased nearly 88% than that from the smooth tube wall. In addition, the pressure drop caused by spiral-gear inserts is in the permissible range of engineering application. The inserts is applicable to the heat exchangers at a flow rate lower than 0.8 m·s^-1 .

Abstract: In this paper, the method of balancing the axial force with balance hole is studied based on the combination of CFD and experimental research. The relationship between the radial position of balance hole and the effect of axial force and external characteristics of the pump is in-depth studied. Research shows that, there are certain laws for the effect of the balance hole location to the axial force and the external characteristics: the overall pressure of the balance chamber and the axial force decrease with the decrescence of the balance hole radial location, which could get good effect on balancing axial force. But the head and efficiency decreased.

Abstract: High vacuum dry pump is a typical technology-intensive mechatronics product. It is mainly composed of a specially designed gas-pumping structure and a set of very complicated electronic control system. Taking place the conventional dry pump unit, this pump can used in many hi-tech area such as semiconductor industry where oil-free high vacuum is needed. This paper introduces two types of dry pump, including their structures and performances. Some key points related to the development of the pump are intensely discussed as well.

Abstract: The thesis introduces a new design for liquid mixing system, which can replace the liquid mixing system based on the PLC or numerous meters. The fact proves the new design have lower cost, smaller volume, higher control accuracy and quick response.

Abstract: The aim of the paper is to reveal the flow structure and the mixing process of a steam-jet pump by using a computational fluid dynamics code FLUENT. Discusses the effect on a steam-jet pump’s entrainment ratio when the throat diameter of the primary nozzle as well as the outlet diameter of the primary nozzle is varied. Analyzes the position of shock wave which will bring the steam-jet pump’s performance a great loss. The performances of a steam-jet pump are studied by changing back pressures while the distance between primary nozzle outlet and mixing chamber inlet (DPM) is varied. The entrainment ratios of a steam-jet pump with different values of DPM and different back pressures are calculated.

Abstract: Using adjustable speed crushing regeneration test device for the recovery experiment of thermosetting phenolic plastic waste, this paper analyses the principle of recovery process. Through particle size analytical technique, FTIR, XRD and SEM etc. various testing method is analyzed mechanochemical effects of crushing process. Research the speed, time, temperature process parameters of the influence of recycling process conditions. According to the experimental results, it established the mechanochemical model and analyzed the degradation and regeneration mechanism of thermosetting phenolic plastic waste.

Abstract: In order to learn the mechanical properties of deep-sea mooring lines, experimental studies involved in strength properties have been carried out in this thesis. In the fiber strength performance test, the small force-large deformation experimental device has been designed and optimized. As the fiber diameter is very small (about 40μm), microscope is chosen to measure the diameter. The intensity curve of fiber is divided into three typical phases. The yield strength, breaking strength and elastic modulus in initial stage can be calculated and the elastic modulus is basically a constant. With the increasing of loading rate, the breaking force reduces and gradually tends to stabilize. It has got the formula, breaking strength ∝.

Abstract: This paper introduced the application of pattern recognition in the measuring phase fraction of gas-powder mixed flow. Flow-through measurement system based on virtual instrument techniques; include the techniques of electrical capacitance tomography and cross-correlation velocity measurement technology. The module structure of the system is present. According the principle of the phase fraction based on pattern recognition technology, the arithmetic with C++ program is described in the paper. The experiment process for this flow-through measurement system and experiment results are described in this article.

Abstract: The experiment on gas jet flame extinguishing with water mist in open space was conducted in this paper. On the basis of experimental result, the process of the flame extinguishment can be classified into two categories:1) when fuel flow rate is small, the gas jet flame can be suppressed and extinguished quickly; 2) When fuel flow is large, the flame lifts from the attached position at the burner exit after suppressed by the water mist. FLUENT is used to simulate the interaction of water mist with gas jet flame. The Eddy-dissipation model (EDM) is used for combustion of flame. the water mist is simulated by Discrete Phase Model (DPM).The simulated results agree well with the experimental results. To some extent, EDM is suitable for simulating the interaction of water mist with a turbulent gas jet flame.

Abstract: With the aim of minimizing the energy consumption cost and taking the billet heating quality as the constraint condition, a mathematical model was established based on the billet heating model to solve the optimum heat institution of the reheating furnace. The tabu search algorithm was employed to solve the model. The results of the industrial production data optimization showed that the proposed mathematical model and the solving method could fully meet the practical production demand of the reheating furnace. In addition to satisfying the heating quality requirements, the energy consumption is reduced and the oxidation loss is decreased. Compared with the original one, the heating institution obtained from the mentioned model and algorithm had a better performance on energy efficiency.