Applied Mechanics and Materials Vols. 170-173

Abstract: The HiTAC technology (High Temperature Air Combustion) is a reliable, industry proven combustion method. A three-dimensional numerical model is established which is for unsteady preheating process in honeycomb regenerator. The preheating period of honeycomb was simulated by means of computational fluid dynamics (CFD) software; the outlet temperature, temperature at lengthways of gas, and temperature at lengthways of honeycomb were obtained.

Abstract: This paper is concerned with the numerical study of gas–liquid flow in bubble columns by large eddy simulations (LES). The Euler–Euler approach is used to describe the equations of motion of the two-phase flow. The mean velocities and the fluctuating velocities are obtained. It is found that, when the drag, lift and virtual mass forces are used, the computed results in agreement with experimental transient behavior can be captured.

Abstract: In this paper, a numerical two-phase flow model combining with the Realizable k–ε turbulent model for compressible viscous fluid is presented for the computation of water drop falling characteristics; and the equations are solved with the finite volume method. The free fluid surface is simulated by the VOF method. A multigrid technique based on the full approximation storage (FAS) scheme is employed to accelerate the numerical convergence. The numerical results for water drop suggest that this basic model can be used to study violent aerated flows, especially by providing fast qualitative estimates.

Abstract: A feature selection method for manual operated directional valve based on EMD and GA-PLS is proposed. Vibration signal from a manual operated directional valve is difficult to find the main fault features. The EMD method is used to decompose the vibration signal into a number of intrinsic mode function (IMF) components. Auto-regressive (AR) model is a time-series tool which can represent the important information of system state. Therefore, AR model of each IMF component is established. The AR parameters and the loss function are regarded as the feature vectors. In order to reduce feature vectors, Genetic algorithm-partial least squares (GA-PLS) is a suitable method for selecting effective features. GA-PLS method is used for selecting new features from these feature vectors, which constitute the AR parameters and the loss function. Experimental results show that this method can be applied to select features effectively.

Abstract: One of the key technologies in recycling cooling system is controlling scale formation, practices have shown that the chemical antisacle method of using inhibitors is the most economic and effective technology. Inhibitors can antisacle by their properties of complexation, lattice distortion and dispersity. In this paper, an easy and effective method of calcium carbonate powder to test their dispersing power is put forward. And by this, the dispersing power of 7 low molecular inhibitors and 9 polymer inhibitors have been determined and ordered, this will provide a significant experimental basis for screening inhibitors.

Abstract: Coal mine drainage, exhaust air and bathing wastewater, etc. contain a large amount of waste heat resource. Using the waste heat effectively is beneficial to achieve energy conservation and emissions reduction and improve economic benefit for coal mine. Heat pump and heat pipe are thermal devices recycling waste heat effectively. The ways and purpose of recycling waste heat in coal mine by using water-source heat pump, air-source heat pump and heat pipe exchanger is given. The performance of heat pump and heat pipe is briefly evaluated.

Abstract: Based on measured ventilation condition in the built aerobic composting plant of large sludge treatment engineering,using the methord of CFD, four kinds of scheme for the new aerobic composting plant were analysed,which contain two types of ventilation(natural air supply mechanical exhaust and mechanical air mechanical ventilation)and two kinds of supply air rates (4x105m3/h and 8x105m3/h). Studies have shown that the methord of mechanical air supply and exhaust is better than the original natural air mechanical exhaust in this plant; The methord of mechanical air supply and exhaust is recommended to reduce ammonia content for personal breathing zone and ventilation energy consumption.

Abstract: The utilization of the solar energy could be promoted by the application of courtyard sunspace, and meanwhile fossil energy consumption could be reduced. Sunspace temperature and ventilation quantity with different vent height was simulated and analyzed. The results showed that ventilation quantity was increase with increasing vent height, and ventilation quantity decrease when vent close to sunspace top, the maximum ventilation quantity reaches 150m3/h based on selected sunspace size. The theoretic principles to improve the sunspace ventilation effectiveness could be provided.

Abstract: Super Stream Duct(SSD) was a new-type hydrodynamic energy-saving device. This paper designed the test model of Super Stream Duct. The resistance trial and the self-navigation trial of the model ship with the super stream duct equipped were proceeded. The influences of geometry shape and the installation position of SSD on the energy-saving effect was analyzed at different flow speeds. The experimental results have shown that the Super Stream Duct can save energy when the ship installed the SSD. When the open angle of profile was 12°(type B), the distance between the SSD and propeller disc was 40mm, the effect of saving energy was the best.

Abstract: The double-energy heating system studied in this paper is consisted of centrifugal sewage-source heat pumps and gas boilers. As the grade and price of the two kinds of energy are different, the heating capacity of the heat-source equipments would have a directly impact on the energy consumption and operating cost of the system. In order to obtain the optimal heating capacity of the heat-source equipments, the calculation models on equipments utilized in this system are firstly established, and then different combination patterns of the heat-source equipments were analyzed on the basis of minimum operating cost, finally, the optimal heating capacity of the heat-source equipments and the heating performance factor (HPF) of the system in different outdoor temperatures were obtained, the results indicate the average HPF of the system in the heating period is 3.57. The method and results provide reference for scientific design of the double-energy heating system.