Research On The Heat Transfer Characteristic And Its Application Of Spray Cooling For High-temperature Materials In Rotary Drums

Drum cooler is an important equipment in rotary hearth furnace process line.Metallized material’s temperature can get as high as 1100 centigrade after through rotary hearth furnace’s reduction,getting into the rotary cylinder of drum cooler and its temperature can drop below 300 centigrade through an indirect radiate way outside the cylinder.Traditional cooling method including the cooling water soaks the cylinder or spray the cylinder,has low efficiency,serious material waste,high cost and bad environmental.The paper takes drum cooler as research project,uses spray cooling technology to replace traditional cooling way.The main purpose of the research is through the analysis of the heat transfer process of spray cooling machine,establishing the heat transfer model,using numerical simulation and experimental method to analyze the process of spray cooling,obtaining the main factors affecting the efficiency of cooling,and designing spray cooling system,improving the steel industry’s high energy consumption and low efficiency by utilizing the analysis conclusions,it has strong application value of engineering.The heat transfer process of material cooling in the drum cooler can be divided into two parts: one is between the particle materialto the cylinder,another is spray cooling process of cylinder wall.For the former,analyze the motion and heat transfer characteristics of particle material in the cylinder,build the heat transfer model between particle material and cylinder inner wall on the base of thermal penetration theory.And the heat radiating area on the outer wall of the cylinder is divided into high temperature and low temperature zone in the axial direction,the circumferential direction is divided into the main radiating area and the auxiliary radiating area.For the latter,build the spray cooling model,conclude the parameters affecting cooling efficiency on the base of pool film boiling.The main radiating area is the main research focus of this paper.For the main radiating area,the spray cooling process is simulated by numerical simulation method,get the atomization characteristics and heat transfer characteristics.The experimental and simulate results show that the heat transfer coefficient of the spray area is in non-uniform distribution which is large in the middle,and reduce on the both sides gradually,the spray cooling efficiency reduces when the temperature increases.In this paper,the heat transfer coefficient and atomization characteristics are analyzed and compared under different spray system parameters.Obtained todecreasethe average diameter and increase the droplet velocity can enhancecooling efficiency,we can realize it by change the inlet pressure,mass flow rate and inner diameter of the nozzle.Through the intercombination of spray system parameters can make the cooling machine to meet the maximum cooling efficiency under different conditions.Through the above research,we can know more deeply about the heat transfer process of spray cooling machine,and the related conclusions are important to the design of the equipment.In the end of this paper,the spray cooling system is designed according to the analysis conclusion and working conditions,summarized the operation condition and verified the rationality of the project research.