''I want you to go"
As we know infinitive works as noun, adjective and adverb.So my question is that here in the above sentence "to go" works for what?
This a complex construction from a grammar point of view. Using the traditional view of grammar, an infinitive is a verbal and cannot take a subject or form a clause (subject + verb). It can function only as a noun, adjective, or adverb. Using this traditional theory with your sentence leaves us with Subject (I) + verb (want) + indirect object (you) + direct object (to go), with the infinitive acting as a noun direct object. Some would object to this analysis because the subject does not want to go -- the subject wants someone else to go (the indirect object). I understand this disconnect. The construction itself logically, if not grammatically, treats the indirect object as if it were the subject of the infinitive. But the traditional view of grammar does not allow an infinitive to have a subject.
If we remove "you" from your sentence, we are left with "I want to go" with the infinitive acting as the direct object of the verb "want". In this case the subject is the one wanting to go (subject + verb + direct object). That is much simpler.