Applied Mechanics and Materials Vols. 300-301

Abstract: Aerodynamic design of airflow duct has become an important issue of the automobile Heating, Ventilation and Air Conditioning (HVAC) system. In this research, the HVAC defrosting airflow duct of a passenger car was designed using Computational Fluid Dynamics (CFD) method. The HVAC defrosting outlets’ sizes and positions were considered as design variables. The mass flow rate distribution and the cabin flow structure were considered as design targets. The steady Reynolds Averaged Navier-Stokes (RANS) method was adopted because it is an efficient way to help select possible good designs in the early stage of new product development without time consuming and huge computational cost of the unsteady methods. Various duct design configurations were evaluated by analyzing the defrosting mass flow distribution of each flow outlet and by visualizing the flow structure near the windshield and the front left side window. The CFD results showed that the total area of the outlets near the rain wipers was a decisive parameter for mass flow distribution in this duct design. The defrosting flow structure near side windows were difficult to be improved only by enlarging the area of the outlet. The effective flow structure was realized by choosing proper angles of the vanes skirt of the outlets to defrost the windshield region. The overall performance of HVAC system, such as defrosting time and cabin temperature distribution, could not only be predicted based on the results of the steady RANS method. It was shown that the important parameters including the mass flow distribution of each outlets and the flow structure near the windshield and side windows could be quickly evaluated from the steady state CFD simulation results in the early design stage.

Abstract: At first, the impeller power generate equipment was introduced in this paper. Second, the instantaneous velocity that the wave got into the equipment and the movement of the wave in the equipment was illustrated. At last, the stress, deformation and coefficient of safety were calculated by ansys under three different height of wave.

Abstract: A purely torsional dynamic model of closed-form planetary gear set is developed to investigate its natural frequency and free vibration modes. The closed-form planetary gear set considered consists of two-stage planetary gear connected by high-speed carrier and ring gear. Three identical planet gears are equally spaced in each stage. Based on the precondition, the natural modes are classified into three types of vibration modes: overall modes，high-speed planet mode and low-speed planet mode

Abstract: In this paper, the test methods of radiation laboratory and data analysis in detail were introduced. The impact of the capillary system with different parameters changing, such as water temperature or water flow the capillary cooling capacity changes, and the capillary cooling system when the initial radiation response time were specificially studied. Under different parameters while cooling capillary volume changes associated with the indoor temperature can be seen under certain conditions, the capillary cooling capacity and room temperature has a linear relationship.

Abstract: In this paper, the numerical simulation analysis of jlu fsae racing car aerodynamic character based on star-ccm+ was introduced. Several simulated situations had been set and the results of the situations were compared. The effect of the wheel rotating situation of the racing car out flow and aerodynamic character was concluded. It was found that the air flows surrounding the wheels and the wings of the racing influenced each other. When the rotating wheel situation was set during the simulation, the effect that the air flows influenced could be simulated more clearly and the result could be more calculatedly. It was necessary to set the wheel rotate when to simulate the racing car aerodynamic character. From the simulated results, it also could be seen that it was also necessary to take care of the wheel rotate when to do the racing car wind tunnel test.

Abstract: By extending classical spectral clustering algorithm, a new clustering algorithm of uncertain objects is proposed in this paper. In the algorithm, each uncertain object is represented as a Gaussian mixture model, and Kullback-Leibler divergence and Bayesian probability are respectively used as similarity measure between Gaussian mixture models. In an extensive experimental evaluation, we not only show the effectiveness and efficiency of the new algorithm and compare it with CLARANS algorithm of uncertain objects.

Abstract: Free-surface model with surface tension and wall adhesion(wetting) is a very efficient technique to simulate two-phase flows with high density and viscosity ratios, such as etching and casting processes. In this paper, a conservative surface tension and wall adhesion model based on lattice Boltzmann single-phase free-surface method is proposed. The effectiveness of the model is demonstrated by simulating the flows induced by wall adhesion and surface tension, and filling processes in a 2D cavity.

Abstract: Aiming at the implanted mandible titanium plate in chewing movement under the action of repeated load is prone to fracture, leading to problems such as secondary surgery. This study makes fatigue simulation analysis for customized implanted titanium plate of fatigue damage. It also analyzes the minimum service life position and low service life area on different loading. Simulation analysis of deformation is done. The analysis contains the deformation area and the maximum deformation degree with a variety of bite condition. This study also analyzes and forecasts the fatigue failure area, which provides basis for preventing fatigue failure for implanted titanium plate. It has important significance to improve titanium plate service life and strength. It also could alleviate patients’ sufferings.

Abstract: The numerical model of the unsteady flow field of ducted propellers is based on CFD (computational fluid dynamics). By applying the numerical model, the unsteady hydrodynamic performance of the ducted propeller with the fracture at different positions of a certain blade is numerically analyzed under three different wake current fields. Based on regress analysis ,the relationships between the mean KQ、mean KT and the quantity of the blade fracture of ducted propellers are obtained; and the relationships between hydrodynamic coefficients Kp, KQ, KFy (Bearing force coefficient of the propeller) and wake current fields , the quantity of the blade fracture are respectively further analyzed. The results show that: (1) with the increase of the quantity of the blade fracture, the amplitude of bearing force periodic variation of propellers increases, while the thrust and torque reduce; (2) the bearing force of propellers is similarly sine-varying, and the frequency of its variation is unrelated to the normal variation frequency of the wake current field. The more non-uniform the wake current field is, the more the amplitude of its periodic variation is; (3) the thrust and torque of propeller are similarly sine-varying, and the frequencies of their variation are related to the normal variation frequency of the wake current field. And the frequencies equal the shaft frequency multiplied the normal variation frequency of the wake current field. The more non-uniform the wake current field is, the more the amplitude of their periodic variation is.

Abstract: The durability performance of PPS filter media is experimentally studied in the paper. It is found that, under 200°C and atmospheric condition, both machine direction strength and transverse direction strength of PPS increase at the beginning and then gradually decrease with the increase of duration time. The transverse direction change for both strength and elongation is higher than the machine direction. The melting point of PPS decreases with the increase of duration time. And the melting point can be taken as one of durability index for the PPS filter media.