| In the context of"carbon neutrality and peak carbon emissions",the development and application of clean energy,particularly lithium batteries,has become a major trend.Mobile electric tower cranes are widely equipped in ports and factories due to their superior performance.Lithium batteries are also used in transportation power sources,power storage sources,mobile communication power sources,new energy storage power sources,and aerospace special power sources.Therefore,the production and application of power lithium batteries are constantly increasing,and their performance is constantly improving.However,as a power source,lithium batteries achieve discharge and charge through chemical reactions,accompanied by the transfer of heat and energy.When lithium batteries are used in large equipment such as electric tower cranes,the working current is large,and heat dissipation is not timely,which can easily cause thermal runaway and spontaneous combustion,posing safety risks.In order to further improve the stability,reliability,and safety of lithium battery use,and solve the problem of rapid heat dissipation in lithium batteries in summer and under high loads,this paper proposes a highly efficient and energy-saving forced heat exchange cooling device for electric tower cranes.This device enhances heat exchange on the basis of immersion cooling by adding jet structures,and actively exchanges heat based on the discharge current of lithium batteries,while also saving energy.The main contents of this paper are as follows:（1）Structural design of cooling device.Based on the operational requirements of an electric tower crane,the number of lithium battery packs required is calculated.Using the theory of free jet,the arrangement of jet nozzles is determined to form an immersed jet forced convective cooling device.Additionally,the design of expansion heat sinks and inlet/outlet for cooling fluid is incorporated.（2）Simulation and orthogonal experimental study of cooling device.Factors such as jet nozzle deflection angle,jet nozzle diameter,coolant velocity,and coolant type are selected as horizontal factors,and the heat transfer performance of the immersed jet cooling device is chosen as the evaluation index.An orthogonal experimental study is conducted to analyze the impact of different factors on the cooling device using the FLUENT software to simulate and obtain key parameters such as maximum temperature,temperature difference,and Nusselt number.（3）Optimization of structural parameters of the cooling device.Aiming at the forced jet heat transfer method with strong heat exchange capacity,the functional relationship between its important influencing parameters and heat exchange is established,and the maximum value of the objective function is used as the optimization goal,and the optimal heat transfer result parameters of the cooling system are calculated through the annealing algorithm that communicates with the cooling principle,and the optimal structural parameters of the immersed jet cooling device are obtained The jet diameter D=8mm,the jet declination angleΦ0=47.50,and the cooling working fluid flow rate ν=1m/s.（4）Research on coolant flow control system.A flow control system scheme is designed,mathematical models of each component are established,and the transfer function of the entire coolant flow control system is derived.Controllability and observability analysis are conducted on the system,and PID and robust control methods are designed.Simulation experiments show that the robust control method for the coolant flow control system minimizes the transient process time.（5）Experimental validation.An experimental platform for immersed jet cooling is set up to verify the cooling performance based on the results of the orthogonal experiment and annealing algorithm optimization.Under set experimental conditions,only changing the coolant velocity,the experimental results show that higher coolant velocity leads to higher heat transfer rate,indicating better cooling performance of the cooling device. |
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