Modeling Development Of Radiation Heat Transfer Of Liquid Droplet Radiators

Liquid droplet radiator?LDR?is a very promising new space waste heat export system for discharging waste heat generated by space power systems,propulsion or spacecraft systems.LDR has many advantages over the prior art,including having a smaller unit power quality,being more compactly stored in a space chamber,relatively easy to install in orbit,and almost immune to threats from lasers,particle beams,and kinetic weapons.It is a space aircraft cooling system with very good prospects.The droplet layer from the LDR droplet generator to the droplet collector is the effective part of the space radiation heat dissipation,thus studying its radiation heat transfer characteristics is crucial for the optimal design of the entire LDR system.Compared with the traditional distribution of LDR droplet temperature as two-dimensional continuous,this paper re-modeling from the aspect of each single droplet to analyze the radiation heat transfer characteristics of the droplet layer.The advantages of this method over traditional methods are mainly:?1?the radiation heat transfer characteristics of the droplet layer are calculated as three-dimensional transient issue,that is,the temperature change in the thickness direction is not neglected;?2?the temperature of the liquid droplet layer is not limited.That is,the temperature of the droplet layer does not need to be continuously commanded.From the perspective of single droplets,the droplet evaporation characteristics and radiation heat transfer characteristics of the sparse LDR system,the radiation heat transfer characteristics between two droplets,the angular coefficient between multiple droplets and the rectangular LDR system are studied.The radiation heat transfer characteristics of the droplet layer,it is found that it is feasible to calculate the radiation heat transfer properties of the individual droplets to obtain the radiation heat transfer properties of the integral droplet layer;and when calculating the radiation heat transfer characteristics of the droplets,the liquid can be ignored.The effect of evaporation of the drops.The radiant heat transfer angle coefficient between the two droplets is only related to the ratio of the distance between the two droplets to the droplet radius;and the radiant heat transfer angle coefficient between the three droplets is only related to three dimensionless constants,₁k,₂k and ₃k,where,₁k,₂k and ₃k are the ratio of the spacing between the three droplets to the droplet radius,respectively.By introducing the concept of general angular coefficient matrix,the radiation heat transfer characteristics of the droplet layer of the rectangular LDR system can be greatly simplified.According to the general angular coefficient matrix,the temperature distribution of the droplet layer temperature distribution on the thickness-width section is uniform.The maximum temperature difference does not exceed 10-4K,so that the rectangular layer LDR system droplet layer radiation heat transfer model can be simplified according to this characteristic.The simplified model calculation results show that the simplified model agrees well with the original model,and the relative error between the two models does not exceed 0.35%.Therefore,the simplified design can be used to improve the design efficiency in the initial design stage of the LDR system.