Advanced Materials Research Vols. 314-316

Abstract: Salt slurry is the solid waste of the salt industry. The study object is the salt slurry before filter in Jianghan Salt & Chemical Complex. This study investigates the application of the salt slurry in Talimu unsaturated brine-based drilling fluid of the carboniferous system in laboratory. It indicates that on the premise of the same density and pH value as the basic drilling fluid recipe, when the salt slurry dosage was less than 500 kg/m3, all the salt slurry application-based recipes measured up both the rheology behavior and the filtrate loss of the drilling fluid. This investigate will reduce the cost of the drilling fluid with the salt slurry as a resource.

Abstract: According to the periodic structure of the plate-fin heat exchanger, 3D model of the heat exchanger is established which simplifies the computation amount of the numerical simulation on flow field and temperature field. The relationship of fluid velocity, temperature, pressure drop and heat transfer coefficient is analyzed. The flow and heat transfer characteristics can be well predicted. Based on the simulation results, the conclusion makes reference to the design of plate-fin heat exchanger.

Abstract: In order to investigate the static pressure loss of the maize deep-bed drying related to the ratio of air flux to grain mass, the experiments based on the theory of thermal engineering and deep-bed drying were engaged in. These experiments conducted on the ventilation test stand indicate the relationship between static pressure loss, depth of the bed, ventilative dimensions and the ratio of air flux to grain mass. The investigation results that during the drying, the static pressure loss increases related to the increased ratio of air flux to grain mass with the constant bed depth. The good linear relationship between the static pressure loss and ventilative dimensions was indicated. With the control of the constant ventilative dimensions, the static pressure loss increases related to the decreased ratio of air flux to grain mass and it will dramatically increased when the ratio of air flux to grain mass is small enough. To reduce the static pressure loss, enlarging the ventilative dimensions, reducing the thickness of the drying layer and reducing the speed of the wind will be the proper methods.

Abstract: The non-destructive pulsed phase thermography technique was used to detect metal specimen with flat blind-bottom holes and composite specimen with sticky areas. An experimental platform was built base on the analysis of the pulsed phase thermography testing principle. Experimental results show the different testing effect of the original thermography, amplitude and phase images.

Abstract: Dealing with a droplet on the flow channel of PEMFC, a mathematical model based on the force balance of the flow force, gravity and hysteresis tension is derived to address the expressions of the critical airflow velocity and the droplet radii. The results show that in the horizontal flow channel, the critical airflow velocity is hardly affected by the working temperature but decreasing with the increasing of operation pressure. The droplet removal capability can be enhance by increasing the tilt angle of the cell. For a small droplet, the operation pressure has an apparent effect on the airflow velocity, while for a droplet in the spontaneous departure area, this effect can be neglected.

Abstract: Recently, the semiconductor manufacturing industry has exhibited not only fast growth, but intense power consumption. Consequently, reducing power consumption is critical for running reliability. A view of literature reveals that the power consumption of facility system is 56.6 % in the fabs. Among all facility systems, chiller plants are the largest energy users, consuming 27.2 % of the total power consumption. Therefore, saving power consumption for chiller plants involves a considerable economic benefit. In addition, cooling the water temperature further improves the efficiency of chillers. Hence, this report analyzes the optimal temperature between the chiller and cooling tower. Currently, controlling the chiller and cooling tower are separate processes, though, in fact, they should not be. This is because the water cooling temperature affects the efficiency of the chiller. Each reduced degree of the chiller condenser temperature reduces the electrical power by approximately 2 % in the cooling tower, in contrast to the chiller. Therefore, the optimal water cooling water temperature must be analyzed. The analysis method in this report is linear regression. First, determine the equations of power consumption for the chiller and cooling tower with variables representing the water cooling temperature, water supply temperature of the chiller, and outdoor loading and wet-bulb temperatures. Second, add the coefficient of the same variable to obtain the total power consumption equation for the chiller and cooling tower. The result shows the relationships of power consumption with water cooling temperature under identical conditions of the water cooling temperature, water supply temperature of chiller, and outdoor loading and wet-bulb temperatures. Finally, use the differential method to determine the optimal water cooling temperature.

Abstract: Using a special Test-Bed, the temperature and the grain moisture content variation in different locations was measured continuously, under the condition of maintaining a large temperature difference between two terminals of grain layer. The results show that the temperature gradient can enhance corn-drying process, and there are two modes of the promotion: 1. The temperature difference direct drive the moisture migration; 2. The temperature difference can generate air convection, and accordingly promote the drying rate. However, the speed of moisture migration originated from air convection was much higher than driven by temperature gradient.

Abstract: A new solving approach for constraint problem was proposed in this paper, the constraint problem needed to solve was decomposed not into single sub-problems, but into three types of sub-problems, namely, rigid subset, scalable subset and radial subset, and each type of subset corresponds a cluster of constraint problem. Based on cluster rewriting rule approach, a small set of rewriting rules were applied in constraint system, and then an incremental algorithm was applied, the generic solution will be get when there is no available rewriting rule to be applied. By this approach, we can determine that constraint system is well-constrained, under-constrained or over-constrained. The results reveal that the proposed method can efficiently process constraint problem.

Abstract: With the continuous improvement of the calculation speed of computer, tool positioning methods based on numerical calculation in five-axis NC programming will play a greater role. First, this paper introduces three numerical methods for calculating tool position error distribution between a torus cutter and design surface in 5-axis machining of sculptured surfaces, namely a method for discretizing design surface, a method for discretizing the torus central circle, and a longitude method. At the same time, the detailed calculating steps are also given. An example of a cylindrical surface machined with torus tool is then conducted to compare and analyze the calculation accuracy and efficiency of the above methods. Results obtained show that the calculating deviation for computing tool position error distribution using the method for discretizing the torus central circle is minimum, while that using another two methods are larger; the calculation time of the method for discretizing the torus central circle is shortest, while that of the longitude method is longest; within the given programming tolerance, the machining strip widths calculated by the above methods are appropriately same, and the maximum deviation of actual machining strip width is within 2% of the theoretical value.

Abstract: A high-precision and efficient machining method of plane double enveloping hourglass worm is proposed. The worm tooth surface is first created and analyzed based on meshing theory. The analysis reveals that the worm tooth surface is a developable ruled surface. This provides the ability of precise flank milling of the worm tooth surface. The meshing lines on the worm tooth surface indicate the contact lines of the worm tooth and the cutter. The five-axis tool path of flank milling is then generated according to the meshing lines. The flank milling has obviously advantages in machining efficiency and surface quality, compared with the conventional end milling method. The cutting simulation and experiment validate proposed method.