To retain rhubarb chunks rather than turning them to mush, try baking them. You need a high heat to get them going, though; and you may find that they take 30 to 45 minutes to braise, even on maximum. Keep checking, and stirring. If you cover the dish, you may end up with too much liquid.
These quantities served 2 of us, being greedy; they might do for 3, or even 4.
3 big sticks rhubarb, washed and cut into chunks
Juice of 1 orange
2tbsp muscovado sugar (or more, to taste - check at the end)
1/2 cinnamon stick
Grating of nutmeg
1tsp vanilla essence
Throw everything into an oven dish and bake (uncovered) at a high heat, stirring from time to time.