Scale and Deposits in High-Heat-Rejection Engines

摘要

Scaling under conditions very similar to those of a heavy-duty diesel engine cooling system was investigated using a newly designed, versatile test stand. The parameters included flow rate, heat flux, hardness, along with bulk fluid temperatures. The hot surface temperature, a critical parameter, was also measured. Results were interpreted in terms of the conditions in the boundary layer at the hot surface. Critical values of flow rate and heat flux existed for scaling under experimental conditions. A quantitative relationship of scale with heat flux and hardness was observed. Deposits produced from testing of different types of commercial coolants, including phosphate based and nonphosphate based, were measured and compared with results from simple beaker tests.