Varnish formation in turbine lube oil and fluid hydraulic systems is an increasingly common problem with power generating units of many types (gas, coal, and nuclear). Varnish forms, a sticky coating on surfaces inside the fluid system, including bearings, coolers, and valves, and negatively affects operation of these devices. Most notably, varnish causes stiction-induced failure of servo-valves. This article examines varnish formation fundamentals, discusses the difficulties derived thereby, and introduces a very promising control method.
展开▼
