Optimum Cooling Based on the Exit Openings Position for Turbulent Mixed Convection in Ventilated Cavities

In this paper, turbulent mixed convection in a ventilated square cavity exposed to a cooling of the blocks is studied numerically. The cavity walls were kept adiabatic except the right vertical wall which was equipped with three blocks dissipating the heat at a constant temperature. The commercial Ansys Fluent code is used and governing equations were established and discretized by the finite volume method. The standard k-ε model is considered for the turbulence modeling and SIMPLE algorithm is used for the pressure – velocity coupling. The objective of the present study is to characterize the best outlet location that provides the greatest effective cooling in the blocks by maximizing the heat-elimination rate and decreasing the total temperature in the cavity. Obtained results showed that the variations of the air outlet position in the cavity and the Richardson number have major effects on the stream function and heat transfer.

The Influence of Graphite Heat Conductor Technology on the Preparation and Crystal Structure of Single Crystal Blade

Graphite heat conductor technology can effectively overcome the mixed crystal defect caused by geometric factors during the forming process of single crystal component. The simulation results show that, As for the component that uses heat conductor technology, the heat elimination condition in the corner of component is improved significantly. Before the melt body generating the supper-cold region at the platform end, the solidification interface will advance into the platform from the blade body with the relatively faster speed. According to the analysis of macro structure, the component with heat conductor, because of the diminution of supper-cold time and supper-cold region, the trend to generate mixed crystal on the platform reduces obviously, on one side near the wall of insulation heater, there is almost no mixed crystal on the platform.

Mechanical and Hydraulic Joint Modeling and Simulation about Elec-Pump

Elec-pump (electric-hydraulic-pump) is a highly integrated combination of electric motor and hydraulic pump, which has smaller size, lower noise and vibration, better heat elimination, and has broad application prospects. In this paper, an elaborately parameterized model of the axial piston Elec-pump is built for the mechanical and hydraulic joint simulation by using the simulation software AMESim and ADAMS. The joint model is composed of the electromagnetic drive model, hydraulic model, the mechanical dynamics model and the mechanical hydraulic interface. The joint simulation shows how the rotor centroid pulsation affects the output pressure of Elec-pump at different outlet pressures. The results depicts that, due to the rotor centroid pulsation, the outlet pressure pulsation rate becomes more than doubled at the revolution of 7000rev/min.

Appropriate Mass Flow Research of Lubricant for Different Oil Groove Type of Wet Multi-Disc

Considering in heat elimination of different oil groove type, simulating accurately heatflux and material parameter through using Fluent UDF function, it is analysed quantificationally how does the lubricant mass flow affecting surface temperature, and when maximum temperature of friction surface is minimum in friction process, cooling lubricant mass flow rate is appropriate mass flow rate. From these analysis, appropriate flow rate is existed in affirmatory oil groove type and load, and different oil groove type has a rather much affect on appropriate lubricant flow rate of multi-disc, radial corner groove need larger flow rate under the condition of adequate heat elimination comparing as double-circle groove.

Study on Flow Field in Different Styles of Blades for Eddy Current Retarder’s Rotor Based on CFD

Eddy current retarder was a retarder braking set used in an automobile, and it can transform kinetic energy or mechanical energy of the automobile into heat energy, and heat energy was emitted around environment by the blades founded in the rotor of eddy current retarder, so flow field within the blade had direct effect on heat elimination and braking performance. In this paper two styles of 2D computational model for the rotor had been established. The flow field between and out of blades were analyzed by using RNG Κ-ε model and energy equation. The velocity distribution, pressure distribution between blades, static pressure on work face and rear face of the blade along radial direction all were accepted. The pressure, velocity and air flux for two styles of the blades had been compared. Numerical analysis of flow field was in favor of improved structure design for the blade.

Coupling Analysis of Heat Transfer in Finned Radiator Based on Numerical Simulation Codes ABAQUS and FLUENT

The heat transfer in solid-fluid coupling system relates to not only the heat transfer process in solid and fluid bodies but also the physical quantity exchange through the boundary. Because some boundary conditions, such as heat flux and coefficient of heat transfer, are uncertain, neither solid body nor fluid body can be separated from the coupling system when the thermal coupling analysis is carried out. A coupling analysis method based on numerical simulation codes ABAQUS and FLUENT was put forward to solve the boundary problem. The two simulation codes were controlled by the interface software which was developed to exchange the boundary conditions between solid and fluid models at each iteration step. A copper finned radiator model and its corresponding air model were built by ABAQUS and FLUENT respectively, and the heat elimination process of the radiator under forced convection conditions was investigated. The heat elimination characteristic of an aluminium radiator was also researched. By comparing with the copper radiator, it can be found that the larger the coefficient of heat conductivity is, the higher the heat elimination efficiency is.

The Atmosphere Effect on Synthesis of TiB2 Particles by Carbothermal Reduction

The carbothermal reduction synthesis process of titanium diboride (TiB2) particles was studied. In the synthesis of TiB2 using carbothermal reduction from a mixture of TiO2, B2O3 and carbon, solid-solid reactions occur. TiO2 particles rapidly react with carbon to TiC, which then reacts with boron oxide and carbon to TiB2. In the vacuum condition, TiB2 particles were formed within 10 minutes at temperature of 1300oC. It seems that a high exothermic reaction eventually results in the increase of reaction rate. In flowing argon atmosphere, TiB2 particles were formed at temperature of 1550oC after a reaction of 0 minute and it showed a finer particle size than that in the vacuum condition. This is attributed to the faster heat elimination due to the flowing argon. In high atmospheric pressure of argon gas such as 20 atm in reaction or cooling state, the synthesized TiB2 particles shows a mixture of diverse sized particles.

Recurrent Heat-Related Illnesses During Antipsychotic Treatment

OBJECTIVE To report a case of recurrent heat-related illnesses associated with the use of benzhexol, chlorpromazine, and zuclopenthixol decanoate. CASE SUMMARY During the summer of 2004, a 48-year-old man with a history of diabetes mellitus and schizophrenia was twice admitted to the hospital because of heat-related illnesses. On both occasions, he had been working under the sun in an open car park. His medications included benzhexol 2 mg twice daily, chlorpromazine 650 mg at bedtime, and zuclopenthixol decanoate intramuscular injection 600 mg every 4 weeks. In the first admission, the clinical diagnosis was heat stroke. He was discharged home on day 14, with precautionary advice against heat stroke. In the second admission, the clinical diagnosis was heat exhaustion. He was discharged home on day 4 and reminded of the precautions against heat stroke. An objective causality assessment revealed that the adverse event was possibly drug related in the first admission and probably drug related in the second admission. DISCUSSION Several drugs can impair thermoregulation during exercise or under conditions of environmental heat stress. Anticholinergic drugs or drugs with anticholinergic effects can inhibit sweating and reduce heat elimination. Neuroleptics (antipsychotics), such as phenothiazines, have combined anticholinergic and central thermoregulatory effects. The set point of the temperature regulation center can be elevated by the antidopaminergic effect of antipsychotics, such as phenothiazines and thioxanthenes. CONCLUSIONS Certain drugs may induce or worsen heat-related illnesses. During a heat wave, special attention should be given to those most at risk, and the importance of preventive measures should be emphasized.