Cut corn kernels from cob and place in a 6-quart crock pot. Use the back of a knife to scrape the cobs to get the milk. Place milk in crock pot.
Add broth, carrots, potatoes, onion, garlic, salt, pepper, red pepper flakes, and thyme to crock pot.
Scatter butter pieces on top.
Cover and cook on LOW for 6 hours.
Remove half of chowder and place in a blender. Let cool some and then blend until smooth. Return to crock pot. (Alternately, you can use an immersion blender. But only use it until about half the chowder is pureed.)
Stir in heavy cream.
Ladle into bowls and top with bacon and green onions.