Study On The Topology And Heat Transfer Performance Of The Microchannel For Phased Array Antenna Cooling

Phased array radar searches and tracks targets by electronic scanning which has distinct features of long distance,high precision,anti-interference and high reliability and plays an important role in modern military.In order to meet the higher requirements of detection range,scanning accuracy,miniaturization and integration,it is required to increase the power density and number of chips on the array.How to effectively control the maximum temperature and temperature uniformity of the chips has become one of the key technologies in the design of phased array radar.Therefore,study on the topology and heat transfer performance of the microchannel for phased array antenna cooling is carried out,focusing on the influence of microchannel topology structure on the maximum temperature and the temperature uniformity of the chips.The main research contents in this dissertation are included as follows:(1)Study on the topology and single-phase convective heat transfer performance of microchannel for a single chip coolingTo enhance heat transfer performance of microchannel for a single chip with ever increasing higher heat flux,different topology structures are designed firstly inspired by natural structures,and simulations on fluid flow and single-phase convective heat transfer performance are conducted.Results show that the spider-netted microchannel yields the best heat transfer enhancement,which could be attributed to the increased heat transfer areas,improvement of fluid mixing and better velocity uniformity.Secondly,the geometrical parameters of the spider-netted microchannel are optimized.Then,microchannel test pieces are manufactued by 3D printing technique and experiments are conducted to testify the heat transfer performance.Finally,the conceptual spider-netted structure is proposed and its performance of heat transfer and fluid flow is also studied to provide a reference for microchannel design at high heat flux.(2)Study on the two-phase flow boiling heat transfer performance of the spider-netted microchannel for a single chip coolingTo examine the two-phase flow boiling heat transfer performance of the spider-netted microchannel,the features of VOF and Mixture model are analyzed firstly.Then the Mixture model is adopted to compare the flow boiling heat transfer performance of the spider-netted and the straight microchannel,and the VOF model is used to observe the vapor distribution characteristics of two structures.Results show that the spider-netted microchannel yields better two-phase heat transfer performance due to its increase of nuclear sites and vapor velocity.Finally,the heat transfer performance of the spider-netted microchannel is verified by the experiments.(3)Study on the topology and single-phase convective heat transfer performance of array microchannel for the multiple chips coolingTo control the maximum chip temperature and temperature uniformity of the phased array antenna,the spider-netted microchannel for high-heat-flux chip cooling is extended to antenna array cooling,and a conceptual spider-netted array microchannel structure is proposed firstly,and the fluid flow and single-phase convective heat transfer performance is studied numerically.Results show that the conceptual spider-netted array microchannel not only enhances heat transfer,but also makes the maximum chip temperature smaller and the chips'temperature more uniform compared to the traditional parallel,tree-shaped and leaf vein-shaped array microchannel.Secondly,the effect of geometrical parameters on its heat transfer performance is studied and the structural adaptability is discussed.Finally,test pieces are made by 3D printing technique and experiments are conducted to verify the excellent heat transfer performance of the conceptual spider-netted array microchannel and study the effects of inlet temperature,inlet flow rate and heat flux on the temperature uniformity.(4)Study on the two-phase flow boiling heat transfer performance of the conceptual spider-netted array microchannel for the multiple chips coolingTo examine the two-phase flow boiling heat transfer performance of the conceptual spider-netted array microchannel,difficulties in the two-phase simulation of 3dimensional complicated models are solved firstly.The proposed solution is to use Mixture model and the multi-scale meshing generation method,which not only guarantees the accuracy of the calculation,but also reduces the number of meshes greatly on the premise of ensuring mesh quality.Then,the accuracy of the simulation method is verified by the experiment.Finally,the simulation method is applied to discuss effects of heat flux and inlet flow rate on the boiling heat transfer,and to carry out the structure optimization for the heat transfer enhancement.Through the researches above,some innovations can be summarized as follows:(1)A spider-netted microchannel for heat transfer enhancement of a single chip at high heat flux is proposed.The structure is designed inspired by the natural spider net on the basis of bionics.Results show that the maximum temperature of the chip is 9.9?lower than that of the straight microchannel at the same heat flux of 1000kW/m~2,and the difference between them is more obvious with the increase of heat flux.Furthermore,a conceptual spider-netted microchannel is proposed with the characteristic of interconnected multiple loops.The conclusions may provide reference for the microchannel design of chip coolig at high heat flux.(2)A conceptual spider-netted array microchannel for the multiple chips is proposed which has distinct features of multiple symmetric groups of conceptual spider-netted microchannels in parallel connection.The structure is derived from the spider-netted microchannel for a single chip cooling and extended to array cooling.Results show that it not only controls the maximum temperature of the chip,but also improves the temperature uniformity among chips.In addition,this topology structure has greater adaptability to the requirements of temperature uniformity in different arrays and different inlet and outlet positions.(3)A modeling method for the complex array microchannel topology structure is proposed.In view of the difficulties from the size of microchannel different from the array by several orders of magnitude,a multi-scale meshing generation method is proposed to reduce dramatically the number of meshes and decrease the modeling difficulty on the premise of ensuring the mesh quality.The complex model is supposed to be divided into several blocks with each block meshed separately and the fluid zone grids meshed only by the priority meshing algorithm.The experiment is carried out to verify the accuracy of this method,which will provide an effective technique for the modeling of complex array microchannel structure.