Hi Jugal, having more than 1 ThingWorx deployed on same machine and same tomcat isn't a good idea as you will likely have to rename the webapp for it to be deployed same tomcat, for your quest to setting up high availability for ThingWorx I would recommend going through these documentations
1. High Availability for ThingWorx 7.0 http://support.ptc.com/WCMS/files/169477/en/ThingWorx_7.0_High_Availability_Administrators_Guide.pdf
2. ThingWorx PostgreSQL High Availability https://support.ptc.com/WCMS/files/169519/en/ThingWorx_PostgreSQL_High_Availability_1.pdf
3. How to configure ZooKeeper in ThingWorx (High Availability)HA? https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS241504&lang=en_US
Hope this helps.
If you want to install HA, on single machine is not enough. Three instences is suggested. Please follow below link for basic ThingWorx HA knowledge. https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS241735&posno=1&q=HA%20tony&ProductFamily=ThingWorx&source=sea…
To be honest, HA is a little bit complex and you may get blocked sometimes. I am setting up my ThingWorx HA recently, if there is any concern, we can discuss together.