21-22 the best review on |Turbocharger Surging

Introduction

In this post on best review on |Turbocharger Surging i will discuss about the following important topics

1. What is Turbocharger Surging
2. Causes of Turbocharger Surging
3. Turbocharger Surging in marine engines
4. Turbocharger surging graph

What is Turbocharger Surging?

The high vibration with audible obnoxious noise emerging from the compressor end of the turbocharger is known as Turbocharger surging. During the breakdown of gas flow scavenge air reversal happens through diffuser and impeller blades to blower side causing the surging. Surging is heavy mass of airflow resulting in vibration in Turbocharger compressor impeller and vanes. During this process, compressor operates abnormally and produces a very high pitched noise and is called as Turbocharger surging.

Take immediate action to eliminate the Turbocharger surging, since surging affects the combustion process of the Engine. Prolonged surging will cause thrust bearing damages due to the production of abnormal axial thrusts.

Turbocharger surging causes

1. Uneven distribution of power in the Engine. Cylinders producing unbalanced power. In this process, the air requirement for the turbochargers will differ and cause surging.
2. The compressor wheel and turbine nozzle ring fouled severely.
3. Chocked exhaust manifold
4. Inclement weather.
5. Reduction of Air through the compressor wheel
6. Air filter and silencer chocked with dirt. 
7. High backpressure after the exhaust manifold resulting in a drop in turbine speed
8. Fouled charge air cooler
9. High cooling water temperature at Cooler
10. Choked nozzle ring
11. Load fluctuation
12. Engine speed fluctuation

Preventive methods for the turbocharger surging

• Carry out the periodic cleaning of air filters, Charge air cooler
• Carry out the water washing and granule cleaning of the turbine side and compressor side as per the prescribed schedule
• Perform the complete maintenance of the turbocharger as per the OEM recommendations
• Periodically perform the shoot blowing of Waste heat recovery boiler 
• Check the Pmax of the engine while recording the EPD engine performance data measurement.

Action to be taken in the event of Turbocharger Surging

1. Reduce the engine speed
2. Check the loading pattern of the engine. If the load is frequently varying, then try to stabilize the uniform load
3. Look for the fire on the Exhaust and scavenge the air side of the engine.
4. Check the air pressure manometer for any fouling of the air filter
5. Check the Coolant temperature of the charge air cooler.
6. Carry out the water washing of compressor side
7. Perform the granule cleaning of the turbine side

If the surging persists even after taking the above action, plan for the following procedures.

• Inspection of Turbocharger nozzle ring. If found damage of blades or abnormal wears down of blades, then change the nozzle ring.
• Inspection of the Compressor wheel. Clean the compressor wheel
• Cleaning of Charge air cooler. Dismantle the charge air cooler and carry out the manual chemical cleaning of the cooler on-air and waterside.

Affect of Surging 

The following components will suffer the damage due to the prolonged surging

1. Fracture in compressor wheel due to vibrations

2. Cracks in Turbine blades

3. Overheating of the bearings

4. Damage to the filter and silencer.

Turbocharger performance assessment parameters

• Output and speed of the engine
• The temperature of the intake air
• Before and after turbine exhaust temperatures
• Charge air pressure
• Lube oil Temp.
• Lube oil pressure
• Compressed scavenge air Temp.
• Charge air temperature after the cooler
• Speed of the turbocharger
• Pressure loss in the air filter

Carry out the maintenance work on the turbocharger as per the following schedule

Every 8000- 12000 running hour

• Complete dismantling of the turbocharger
• Measurement of clearances as per the Instruction manual
• Carry out the cleaning of the compressor and turbine casing, Inspect for any cracks and erosion/corrosion marks
• Cleaning and blowing through the ports of the bearing casing
• Clean and inspect for cracks and erosion on nozzle ring.
• Inspection and assessment of rotor and bearing parts

Every 36000 running hours

• Repeat the maintenance work as per the 8000 to 12000 running hour schedule.
• Replace the bearings ( use the genuine bearing )

Significance of Turbocharger speed variations

Drop-in Turbocharger speed

• Damaged bearings & Rotor components
• Connection of defective cylinders during the pulse operation of the turbocharger
• Leaky or faulty exhaust manifold or charge air ducting.

Increased Turbocharger speed

Dirty turbine

Precaution;

Let the engine idle at least for 10 to 15 minutes for the lubricating oil to flow in the turbocharger to dissipate the temperature in the turbocharger bearings.

Compressor cleaning during operation

Wet cleaning of the compressor is only for cleaning the compressor with clean water and is subject to permission from the engine manufacturer.

The density of the dirt deposit will depend upon the cleanliness of the atmospheric air. The dirt deposit on the compressor wheel will be due to the following elements in the air.

• Oily mist
• Solid combustion substances
• Different kinds of other dust particles.

An adverse effect of the above elements will be on the compressor efficiency and reduction in charge air pressure.

Due to the above negative, effects there will be a rise in exhaust temperature and elevated fuel consumption. The deposition of dirt will also cause the rotor to unbalance.

Compressor cleaning should be carried out between 25 to 100 engine running hours, depending on environmental conditions.

Cleaning Method

Wet cleaning of the compressor wheel is strict as per the Turbocharger manufacturer’s guidelines.

All the turbocharger manufacturers approve the wet cleaning method since the technique is easy and safe.

In this method, water is injected into the compressor wheel from a built-in injection pipe.

In this process, water use is not to act as a solvent but to create a mechanical impact of the drops on the compressor wheel. This process is the most suitable process for moderate dirt deposits. For cleaning the advanced dirt deposits, follow the OEM guidelines.

Turbine blades and nozzle cleaning process in operation  

The combustion process of heavy fuels creates the accumulation of dirt on turbine blades and nozzle rings. Following products of combustion are responsible for the deposits.

• Ash/soot
• Cinders
• Un-burnt fuel Sodium vanadate vanadyl

An increase in dirt deposits requires proper cleaning. If not cleaned, it will cause an increase in charge air pressure, reduce turbine efficiency and increase engine temperatures. Engine out will be affected. Heavy deposits will also cause the turbine rotor to unbalance.

Follow the guidance for the cleaning method from Turbocharger manufacturer instruction manuals.

Conclusion

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Good Luck!!!