pressure pulsations in fuel system due to slow steaming?

[DYV1973]

LS,

A superintendant informed me about the fact that slow steaming could cause heavy pressure pulsations in a ships fuel system. Can someone explain why this happens / what causes this phenomenon? Is there someone who has experience with this, and may be also in combination with a large variation in (measured) fuel consumption, and have an explanation for this as well?

Thanks in advance,
DYV

 

[chief]

Fuel pulsation is a common feature of multi-cylinder diesel engines, medium speed .It is caused by the differential pressure between low pressure supply fuel and the high pressure fuel pump delivery. To counter-act it, ensure a positive low pressure supply and fit nitrogen charged pulsation dampers on the low pressure supply fuel rail. The nitrogen charge should be approx. hald of the high pressure delivery pressure.

Offshore Engineering&Design

 

[DYV1973]

Thanks Chief for your reply. I am aware of pulsations in a fuel system, but problem for this specific case is that it only occurs during slow steaming. Could a retaining valve behind the engine cause this, if it comes in resonance with pulsations of the fuel pumps, which is then not happening at higher engine rpms / loads?

DYV

 

[BrianBT]

For a system utilising Bosch type scoll pumps Its casued by increased spill, there is a pulsation damper in the spill line that should be removing this effect. I imagine this is much reduced with Constant High pressure systems

 

[EdStainless]

In some cases I have seen it in land based engines at low load (and low fuel consumption) where the PRV cycles too abruptly. Adjusting the pressure relief/spillback on the LP side fixed it.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube