OPTIMIZATION OF THE DEVELOPED OUTER SURFACE OF AN INDUSTRIAL OIL COOLER

Heat removal from the working liquid of hydraulic systems requires the use of heat exchange devices - oil coolers with their geometry directly affecting their efficiency. This paper considers the issues of statement and implementation of the numerical experiment to solve the optimization problem for the industrial oil design.

Case Study: Consecutive Failure of Lube Oil Cooler Fans Coupling

Do we analyze on why can even the most reliable turbomachinery are getting failure and stopped? In some cases, it's all about bad installation or design literally. This paper explores the challenges one site had with repeated failure of lube oil fin fan coolers coupling which caused the unit availability of more than 3 months. It outlines the troubleshooting attempts made to remedy this issue, its root cause, and the resulting solution. This issue occurred at a site with a train configuration of motor driven centrifugal compressors. The plant lube oil system has been configured with 3 trains. Each train has been configured with Main electric motor + Vorecon Gearbox + Low Pressure centrifugal compressor + High Pressure centrifugal compressor. Lube oil system of the train has been configured as 2 lube oil coolers and 2 working oil coolers. Lube oil coolers are having fins with air cooler type. Air is supplied by fin fans and each train has 2 lube oil cooler fans and 2 working oil cooler fans. In total site has 3 trains x 4 fin fans so it has 12 fin fan cooler fans. All cooler fans are driven by electric motor which is coupled with gearbox and gear box is connected with cooler fan. During normal operation of working oil cooler fan A- stopped rotation suddenly from normal operation. During investigation, motor shaft was found running freely. No movement was seen on cooler fan. Coupling between motor to gearbox was inspected. Coupling is shear plate coupling. Its spacer flexible element were found broken into several pieces. Further investigation revealed that motor coupling hub was moving free axially back and forth due to clearance between motor shaft to coupling hub internal diameter. Motor side Coupling hub bolt hole was found with loss of material and ovality in shape. Hub locking Allen screw was found in damaged condition. Missing materials were noted and broken shear plate materials were found around coupling guard area. While site team was conducting the investigation on the unit A, similar incident occurred in next unit and other 3 units with 2 days difference between them. During detailed investigation it has been noted that all motor to gear box coupling are shear plates and shear plates were broken. Coupling hub was found loose and coupling hub locking screw was found broken or partial damage.

A Study on the Flow Resistance of Fluids Flowing in the Engine Oil-Cooler Chosen

Oil-coolers are necessary components in high performance diesel engines. The heat removed by the cooler is a component in the total heat rejection via the engine coolant. Oil-cooler absorbs the heat rejected during the piston cooling and engine rubbing friction power loss. During flows of both coolant and engine oil via the oil-cooler, some flow resistances occur. The aim of the study is to determine values of the flow resistance coefficient for oil going through the cooler at various temperatures. The test stand was developed to determine time needed to empty tanks from liquids flowing through oil-cooler. The flow model was elaborated to study the mentioned flow resistance coefficient with respect to changing liquid temperature. The 20 °C increase in liquid temperature resulted in a flow resistance coefficient decrease of 30% for coolant and of the much more for engine oil. It was found that better results would be achieved with flows forced by means of pumps instead of using gravitational forces on the test stand.