A build of Mupen64Plus exists which has extremely partial support for the 64DD, but AFAIK all dumped games crash during the startup sequence/menus (nothing playable). Zelda OOT +Disk gets to the save/load screen, but crashes on load. Other games don't even get that far.
It's possible to load the IPL ROM (BIOS) from the 64DD into Project64/Daedalus, but all you get to look at is the boot animation as no drive HW is emulated.
Also, I believe that very few 64DD games/disks have been dumped at all (and doing so is not an easy task).