What will happen to you if you're standing near exploding TNT bomb near 20meter away in Vaccum? What I think here could be ,that we'll feel less powerful shock wave as there is no medium of air through which gases can travel . If their is any other possibilities than please suggest !
 A: You'll want to add some numbers to your question if you want someone else to do some calculations.
For a simple answer:


*

*In a vacuum 


*

*Sound does not travel so you wouldn't suffer overpressure damage to the same extent, though depending on the size of the explosion it could fill the vacuum and increase the pressure enough to kill or injure you.

*Any shrapnel will travel faster in a vacuum, doing more damage.

*" ... Outer space explosions tend to manifest a spherical 'cloud', reminiscent of other space-based explosions ...".


*Underwater (opposite situation)


*

*Sound travels far, and pressure a short distance, resulting in a bubble pulse.

*Shrapnel won't travel very far.

*Direct contact of an exploding device enhances the explosion because the pressure of the water helps direct the explosion towards the most forgiving direction (you, or a sub).
In your case the combination of air and vacuum is closer to the 'all vacuum' example rather than the opposite 'underwater' example. It depends upon what numbers we are talking about whether 20 meters makes a difference, as does the extent of the vacuum and composition of the container.
A huge explosion will create plenty of vacuum. Small explosions are used to protect against explosions in the Iron Curtain or explosive reactive armor methods of tank protection.
