Research On The Thermal Balance Of320Tons Static Pile Driver’s Hydraulic System

The static pile driver has occupied most of the pile market because of its highly efficient piling speed, low noise and so on. The thermal balance teperature of hydraulic system is very important for operating. The study of causes and rules of the thermal balance of hydraulic system is of great significance for improving its efficiency and life.The major work and creative content of this paper are as follows:1、We analysed the thermal performance of static pile driver’s hydraulic system, and we made theoretical thermal calculations of hydraulic system in the different working conditions. We found that the maximum heat element was hydraulic pumps and the most efficient cooling component was the hydraulic oil tank.2、We made comparative analysis of thermal balance of the3200kN static pile driver’s hydraulic system in the vertical shift, rise and piling conditions. We draw these conclutions that in the vertical shift and rise conditions, the producing heat and the cooling heat are same, and hydraulic system reaches thermal balance and the oil temperature doesn’t change; in the piling condition, the producing heat is20.27kW, and the cooling heat is11.08kW, and hydraulic system doesn’t reaches thermal balance and the oil temperature rises. In the three conditions, the hydraulic pump’s power loss is the most, and it takes57.75%、64.0%and49.39%in the whole power loss. We reduced the thermal balance temperature by increasing cooling tubes in the oil tank.3、With the fluid and heat transfer simulation software FLUENT, we completed simulation and analyse of the flow field and temperature field before and after optimization of static pile driver’s oil tank. After increasing cooling tubes, the whirlpool in the tank has weakened, and the zero heat transfer zone has reduced. The oil cavities far from oil returning cavity cools obviously, and the oil temperature has reduced from348.12K to344.16K. If the oil rate increases,the partial energy loss will raise and cooling effect will weaken. And we got the relationship of rate and temperature by simulation.4、We analysed the oil temperature curves of two3200kN static pile drivers before and after optimization. After optimization, the thermal balance temperature reduces from74.22℃to71.1℃, and the cooling tube bundle effects obviously, and we prolong3200kN static pile driver’s continuous working time in high temperature environment.