| Climate change,energy scarcity,and ozone layer depletion are just a few of the environmental issues the globe has been dealing with since the turn of the twenty-first century.Our nation has increased research and development on new energy vehicles in order to meet the objectives of’carbon peak’ and ’carbon neutrality’.Chip integration is expanding along with the development of intelligent electric vehicles,which raises heat flow.The functioning of electronic devices will be impacted by excessive heat accumulation,which might possibly result in damage.As a result,one of the key factors limiting the development of electric cars is the thermal management of electronic components.The need for a quick and effective heat dissipation technique for electrical devices is crucial.In comparison to traditional heat dissipation technology,ionic wind cooling technology provides benefits such as high efficiency,low power consumption,no noise,and a simple construction.Unfortunately,the ability to increase ionic wind intensity only by altering operational or structural characteristics has reached a limit.In this work,a multi-stage ’needle-to-ring’ ionic wind cooling system is suggested to further increase the ionic wind intensity.Combining numerical simulation and experimental investigation,the multi-stage ionic wind cooling system’s operational performance is investigated.In order to investigate the light output properties of LED chips,two different types of ionic wind cooling systems—one for uniform heat source and the other for hotspot—were used in high-power light-emitting diode(LED)thermal management.The following are the primary research contents:(1)In COMSOL,a two-dimensional calculation model is created.In the model,the electrostatic field,charge field,and flow field are all coupled.To investigate the ionic wind flow distribution within the generator,the electric field strength,charge density,and body force are all computed and simulated.The findings demonstrate that the ’needle-to-ring’ generator’s output of ionic wind will collide with the ring electrode,produce eddy current at its top edge,and form reflux at its central axis,all of which alter the wind speed at the outlet.Under the influence of the electric field force during the discharge process,the distribution of charge density is uneven,which causes the ionic wind flow to be unevenly distributed.Optimizing the positioning of needle electrodes can significantly enhance the ionic wind flow.The retractable structure will concentrate a majority of ions at the generator’s outlet,which will cause them to collide with the wall as it moves.This will increase the horizontal force of the ions,decrease the vertical force,and lower the effective wind speed.The optimized double ground ring construction boosts the collecting of charged particles in the air to speed up ion movement,increases the ionic wind flow area,and decreases ion collision at the output.(2)To investigate the electrical properties,ionic wind strength,wind speed distribution,and conversion efficiency of generators with various structures,a test system for ionic wind strength was built up.The experimental results demonstrate the secondary function that numerous collectors may play in speeding the movement of ions,and they also demonstrate that the twostage device in series generates an ionic wind at a velocity that is 32-46% greater than that of the single-stage structure.For various emitter combinations,the wind velocity and flow dispersion are also varied.The double ground ring’s multi-stage design may efficiently enhance the ionic flow area,decrease ion collisions at the output,increase the collection of charged particles in the atmosphere,and speed up ion movement.So that the maximum output wind speed can reach 2.46m/s,and the covered area of the ionic wind flow can also be significantly increased.(3)A heat dissipation performance test system was constructed in order to investigate the cooling performance of the multi-stage ionic wind system.In order to dissipate heat from a uniform heat source and a high-power LED chip,respectively,an optimized and improved ionic wind system was used.The fluctuation rule of temperature,system thermal resistance,and the mean heat transfer coefficient of the heat source were investigated.The multi-stage generator with diverse emitter combination structures and a uniform heat source has a more noticeable cooling impact on the heating surface.The two-stage ionic wind generator performs better when the heat source with high power and high temperature is cooled.High speed ionic wind created in the middle of the generator dissipated the majority of the heat during the cooling process of an LED chip.The double ground ring’s multi-stage construction can drop the junction temperature from66°C to 33°C,and the cooling time is 13 minutes,so the heat dissipation effect is impressive.The surrounding ionic wind speeds up the air flow at the heat sink fin.(4)A test system for LED optical characteristics measurement was built in order to investigate the photometric and colormetric characteristics of LEDs under the influence of a multi-stage ionic wind cooling system.The variation rule of the luminous flux,luminous intensity,and chroma properties were explored when various structural configurations were used.The findings reveal that using a multi-stage ionic wind cooling system,which is 28% more effective than using a single heat sink cooling system,causes a quick increase in the chip’s luminous flux and a gradual decrease in light intensity.The color temperature deviation is reduced,just-0.003,the color rendering index varies less,and the visual impression is better since the LED chip’s chroma coordinate is close to the white light region.The study showed that the multi-stage ionic wind cooling system created for various heat sources may be optimized to significantly increase the heat dissipation efficiency.The optical output properties of the chips may be successfully enhanced when the structure is utilized for the thermal management of high-power LED chips.It also offers a brand-new system for thermal management of electronic devices. |
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