Several of these images, as well as a description of how to create similar images can be found in the book Texturing & Modeling : A Procedural Approach, Second Edition.
Also, please see the work of two students working with me in this area:
This image from a 1990 animation shows procedural volume modeled and rendered steam rising from a teacup with self accurate gas shadowing and illumination.
This image from 1994 has color corrections from the previous image plus the addition of procedural textures on the tabletop and the wallpaper.
This image from 1993 is from an animation showing a single column of smoke rising. Notice the subtle smoke shadows on the wall.
This image shows flow constrained into an opening in the wall. The image on the left is rendered as a volumetric gas. The image on the right is rendered as a volumetric liquid (hypertexture).
This image is a title shot from our ~2 minute animation featuring Pierre's exploration of an art gallery and a fog filled world. It features 30 seconds of volume rendered fog.
This image is a shot from the second scene of our animation featuring Pierre's exploration of an art gallery and a fog filled world. It features 30 seconds of volume rendered, procedurally animated fog.
This image is from an animation showing procedurally animated gas rolling in and enveloping the scene..
This image is from an animation showing procedurally animated gas flowing around obstacles.