what causes an ankle uler wound to drip a clear liquid and can it ever heal?

The clear liquid is plasma. Until this dries, your wound will not heal. I would suggest trying two things.

First, clean your wound and cover in the best clear honey you can afford (ideally organic). Leave open if you can. Do this every day for 3 weeks. In the UK, Liverpool Univeristy devleoped honey pads, but I have not seen them on sale. Many surgeries are now using honey to cure ulcers.

The other thing you should do is, as the pain lessens, try to get more exercise, even walking up and down stairs or round a room and this helps with circulation.

If the honey is not working, try aloe vera. Holland and Barrat sell organic filleted aloe vera, but obtaining from a plant would be better. Again place on your wound every day and leave. Aloe vera is great for skin, soothing right away. A great healer. I use on burns immediately, works every time.

 good luck, my relative has the same issue, but cannot use honey or aloe......