Inlet Guide Vanes
 

can anyone please tell the purpose of inlet guide vanes in the Jet Engine, and whether they also help in preventing the compressor surge, and if yes, how?

Put simply, guide vanes direct the air flow so that it impinges on the compressor blades at the optimum angle to induce most 'lift', ie. most rotational force.

The guide vanes can be variable, ie. they move mechanically, so they can be adjusted for different performance in different flight regimes. They would, therefore, contribute to the flow velocity, which is a key function in compressor surge.

most of engines have the guide vanes coupled to bleed valves.
Not the bleed valves used for the pressurization to keep the subject clear.
At low rpm the guide vanes are position to the optimum angle while the bleed valves pen to increase flow and therefore avoid surge or chocking as it is referred by many.
Usually guide vanes on large commercial engines use return fuel as muscle.

thanks a lot for all the help