Advanced Materials Research Vols. 588-589

Abstract: This paper deals with supersonic/hypersonic flutter analysis of panels. A 3-D rectangular plate element of variable thickness based on absolute nodal coordinate formulation (ANCF) has been developed for the structural model. A continuum mechanics approach for the definition of the elastic forces within the finite element is considered. Both shear strain and transverse normal strain are taken into account. The aerodynamic force is evaluated by considering the first-order piston theory to linearize the potential flow and is coupled with the structural model to account for pressure loading. A provision is made to take into account the effect of arbitrary flow directions with respect to the panel edges. Aeroelastic equations using ANCF are derived and solved numerically. Values of critical dynamic pressure are obtained by a modal approach, in which the mode shapes are obtained by ANCF. A detailed parametric study is carried out to observe the effects of different flow angle directions and aspect ratios on the flutter boundary.

Abstract: Numerical schemes play an important role on the calculation of aerodynamic heating in hypersonic flows. An appropriate scheme can effectively distinguish shock, and reduce numerical dissipation to improve numerical resolution near the wall. In this paper the second order TVD (total variation diminishing) scheme was improved to automatically adjust the numerical viscosity, which can appease the above requirements. In this paper two numerical experiments indicated that the numerical method was effective.

Abstract: This paper studies the possibility of using heat pump instead of cooling tower to decrease temperature and recover waste heat of circulating cooling water of power system. Making use of heat transfer theory the paper carried on analysis and calculation about recoverable waste heat of circulating cooling water in hot-stamping power system which includes hot-stamping, closing in and extrusion intermediate frequency induction furnace. The results show that the whole process can recover calories which is 2.642×106kJ per hour.Using the recycled calories can make 15.82 tons hot water per hour which is 60°C. This research shows that using heat pump to recover the waste heat of circulating cooling water is effectual.

Abstract: In the freeze-dryer, the dual-evaporator refrigeration system is used to meet the demands of the freeze-drying technology. One evaporator is used as “cold trap”, and the other one, shelf evaporator, is used to control materials’ temperature. In this paper, experimental study on the dual-evaporator refrigeration system in the process of freeze-drying is carried out. First, the influence of valve opening on the dual-evaporator refrigeration system is analyzed. Secondly, the influence of vacuum on the surface temperature of the heat exchanger is analyzed. Finally, the influence of the varied evaporation temperature on the first drying rate is analyzed.

Abstract: There are large quantities of heat is wasted in the producting process of cylinder drop stamping part, it is necessary to recycle the heat from the perspective of environmental protection. In this paper the waste heat recovery system that based on heating pump were analyzed, building up cylinder drop stamping normalizing temperature curve and observed metallographic microstructure of the samples at different temperatures. Rapid establishment of geometric model through the use of Pro/Engineer, application of Pro/Mechnica analog normalizing temperature curve, observed the cross-section temperature field nephogram. Based on the analysis, been established by virtual prototype thermal analogue in the Pro/Mechnica with the measured cooling process is consistent. waste heat recovery system which is used in the production of cylinder drop stamping part is effective.

Abstract: According to the principle of heat transfer, the temperature field equation in the leeward tunnel was set up and the experimental device with a ratio of 1:20 was built. When it happened to fire in roadway, the correctness of the temperature field equation can be verified by the experiment. In experiments, the armored thermocouple and color paperless recorder were used to record the temperature of each measuring point. The S-3-300 pitot tube and YJB-2500 compensation micro-manometer were used to determine the wind speed. When the mine roadway fired, the experiment determined the temperature field equation experiment coefficient of Kc. It showed that in the developing phase of the fire K_c = 15 ~ 20, in the stable phase of the fire K_c = 10 ~ 15, in the failing phase of the fire K_c = 20 ~ 25.

Abstract: In this paper, a high power- LED package model has been built. Different bonding materials and substrate materials have been chosen. Having performed simulations of the temperature field by ANSYS finite element software, the conclusions are drawn as follows: nanometer silver paste has the best heat transfer characteristics; ALN is an ideal substrate material because of its lowest junction temperature, thermal resistance and the maximum heat load when the junction temperature reaches120 ° C .

Abstract: Finned tube heat transfer process was analyzed in this thesis, the optimal mathematical model of the fin efficiency and fin volume which was acted as the objective function is established based on the model of heat transfer theory. The heat exchanger numerical simulation of finned tube is taken by the ANSYS finite element program in heat transfer process, and the finned tube structure parameters ( fin spacing , fin thickness , fin height) were analyzed , the optimum structure parameters of a set of finned tube were obtained at the same time. These studies will have some guidance on the application of finned tubes.

Abstract: A theoretical research of the flow and heat transfer inside two longitudinally corrugated tube is carried out. An approximate model is presented by applying perturbation expanding to the governing flow and energy equations. Obtaining the solutions, effects of the amplitude and number of the wave surface of the corrugated wall on the flow and heat transfer are discussed.

Abstract: In order to find out the reason for deformation,cracking and leakage of the shielded can of nuclear canned motor and put forward the solution,a finite element model of 2-pole and 8kW canned motor in temperature field was created. Assigned materials and boundary conditions to each component and calculated the temperature distribution of the canned motor by equivalent heat source load method and display the distribution visibly.By combining with the temperature field data,obtained the temperature characteristics of the shielded can and calculated the thermal deformation based on the maximum temperature.The result of analysis show that the temperatures of each component are different,shielded can’s temperature rise is not uniformly distributed along the circumferential direction and the degree of thermal deformation along axial direction is larger than that along radial direction.The conclusion of this paper is conducive to understand the temperature distribution in canned motor and characteristics of thermal deformation in shielded can clearly,and provides an important theoretical basis for the development of new shielded can structure.