Sep 15, 2019
Diesel engine operating conditions (load, speed) change The diesel engine operates at low speed and high load. When the diesel engine fails or the ship is fully loaded, the top wind and the dirty bottom increase the external load, the diesel engine speed decreases, and the governor automatically increases. The fuel supply allows the diesel engine to operate at low speed and high load. As the amount of oil supply increases, the energy of the exhaust gas increases, which inevitably leads to an increase in the speed of the supercharger, and an increase in the displacement and discharge pressure of the compressor. At this time, the diesel engine has a low rotation speed and a small air consumption, so that the balance between supply and demand between the turbocharger gas supply and the diesel engine gas consumption is broken. Compressor back pressure rises, flow decreases, causing
When entering the low-temperature sea area, the air density becomes higher due to the lowering of the ambient temperature, the intake air volume of the compressor becomes larger, the energy obtained by the turbine is increased, and the supercharger speed is increased to move the running line to a lower position, and the surge is increased. The margin increases; while entering the high temperature sea area, the opposite is true, that is, the surge margin is reduced and surge is likely to occur. For some ships, the supercharged diesel engine without air cooler matched in the low temperature navigation area sails in the high temperature sea, or when the supercharged diesel engine with air cooler matched in the high temperature navigation area sails in the low temperature sea area, because of the match between the two The relationship changes and the operating point is easily close to the surge zone, causing surge.
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