Numerical Simulation Of Heat Transfer Characteristics And Field Synergy Principle Analysis Of The Ribbon-Tubular Radiator

The Ribbon-Tubular radiator acquire an extensive application in the engine radiator of the modern small car and the evaporator and condenser of the autocar air condition system for its structure tightly packed, mass light characteristics.The heat transfer unit of the Ribbon-Tubular Radiator is the louvered fins. The main structure parameters of the louvered fins have material effect to the heat-transfer property of radiator and the resistance performance. Firstly, a cyclical louvered fins heat exchange channel geometry model is establish in the paper, and according to the actual operating conditions and radiator shape it is simplified to a certain extent. Then the louvered fins geometry model is meshed and numerical calculated with computational fluid dynamics software. According to the calculation results, the air side flow field and temperature field distribution rule of the louvered fins are analyzed. The results showed that louvered fins heat transfer effect of aggrandizement is weak in lower inlet velocity of air, and it begins to stabilize in high entry air velocity. The import and export pressure drop of louvered fins heat exchange channel rises intensely in high entry air velocity.According to orthogonal experiment rules,18 different parameter combination 3D geometric model of the louvered fins are established, and 9 radiator operating conditions are set by changing the air inlet velocity. Through comparing the calculated results, the influence law of design parameters to fin surface heat transfer coefficient and import and export pressure drop are analyzed. The influence degree of design parameters are analyzed using extreme difference analysis method. The results showed that within selected structure parameter range, fin surface heat transfer coefficient decreases with the increasing of fins spacing, fin width, fin thickness and decreases with the increasing of louver angle, and fin surface heat transfer coefficient decreases with too large or too small fin length and louver width. Air pressure drop of import and export increases with fins spacing, fin width, louver width increases with the increasing of the fin thickness, fin length, louver angle, and air import and export pressure drop is less affected by the louver spacing. The finned surface heat transfer coefficient differential value of various factors changes with the inlet air velocity. In low flow, the biggest influence on surface heat transfer coefficient of parameter is the louver thickness and the louver spacing, and the smallest one are louver width and louver spacing. Velocity over 5.0 m/s later, the biggest influence on surface heat transfer coefficient of parameter is the fins spacing and the smallest one is louver width. The import and export pressure drop differential value of various factors remain stable. the biggest influence on of parameter import and export pressure drop is fin length and the smallest one is louver spacing.From field synergy principle perspective, this paper analyses the existence of the louvered fins in improving finned convection heat transfer condition positive role, and summarizes the influence law of the structure parameters of louvered fins to the field synergy angle. The results show that the air flow field synergy angle appears uneven distribution phenomenon for the influence of the louvered fins. The field synergy degree of the louvered parts is better than the unlouverd parts, This reflects the louver have reinforcement in improving the heat transfer between air and fins. Within selected structure parameter range,, field synergy angle increases with the increasing of fins spacing, and decreases with the increasing of louver spacing and louver angle, the effect to the field synergy angle of fin width, louver width relates to air velocity, fin thickness and fin length have little impact to the field synergy angle.The related research conclusion of this paper can be used as references of the optimization design of Ribbon-Tubular Radiator, and an evaluation method of the comprehensive heat transfer performance of Ribbon-Tubular Radiator. From the Angle of field synergy to evaluate the heat-transfer property is a new attempt, the related research can be used as a reference of the project optimization design and performance evaluation.