Investigation of the efficiency of the heat exchange process in the MO-2 cooler of turbine oil depending on the arrangement scheme of tubes in tube grids.

Abstract

Effective cooling of the turbine oil is important for the reliability and optimal operation of the turbogenerator. The oil is used for lubrication and cooling of the support and radial bearings of the turbine, bearings of the generator and reducer, gears and splined rollers. It is also used as a hydraulic fluid in the hydraulic turbine start-up system. For reliable and safe operation of the system, it is necessary to maintain the correct temperature of the lubricant. Research is aimed at studying the influence of the layout of the heat exchange tubes in the tube grids on the cooling efficiency of the TP-22 turbine oil. With the help of the SolidWorks software complex, a geometric model of the MO-2 turbine oil cooler was created with three schemes for the placement of heat exchange tubes in tube grids: corridor, radial and checkerboard. Adhering to the parameters of the technical characteristics of this cooler, the nominal parameters of temperatures and consumption of coolants (cooling water and turbine lubricant TP-22) were chosen. The result of the calculations were the temperature fields of the coolants and the trajectories of the movement of lubricant particles in the intertube space of the cooler. When creating a geometric model and further research, the main technical characteristics of the shell-and-tube horizontal cooler MO2 were adopted, namely: the temperature of the turbine oil at the inlet is 45°С, the nominal flow rate of the oil is 3.1 m3/h, the temperature of the water at the inlet is 20°С, the nominal flow rate water - 15 m3/h. The conducted computer modeling made it possible to investigate the influence of the layout of the heat exchange tubes in the tube grids on the cooling efficiency of the turbine lubricant in the MO-2 shell-and-tube cooler. It was shown that the most effective, among the studied schemes, is the checkerboard arrangement of heat exchange tubes in tube grids. This scheme makes it possible to reduce the consumption of cooling water, relative to the nominal one, which will allow the use of water pumps of lower power.