In the old days when there used to be plenty of oil & grease leaking out of engines, I used to steam clean (or jet wash) my engine bays, but unless there has been a mechanical problem, the only thing that's likely to be in the engine bay these days is general road grime.
Its really not a good idea to be spraying water all around the engine bay as it will start the corrosion process on pipes and connectors that otherwise would never get wet.
I've kept my engine bays clean for many years now by just using a damp duster or microfibre cloth and a bucket of car-wash n wax shampoo.
On some of the plastics, I use a plastic cleaner spray (like Autoglym interior shampoo or Comma Interior Cleaner)... and I use metal wadding like Duraglit on some of the metal pipes and other metal surfaces...
Whatever you do - don't stick your arm anywhere near the engine bay to clean it with the engine running. There are moving pulleys, belts and fans that could injure you. And yes - if you get any quantity of water into the air intake, it could seriously damage the engine....