Can I submit an article just for the sake of useful feedback? I have made some research about a topic in Computer Science. The issue was that I am a little bit dubious if the procedure that I followed was correct. The problem gets worse because the work is not in the field of expertise of my supervisor or of my colleagues.

For that reason, I am thinking to submit it to a conference for getting valuable feedback. Would that be reasonable to do that? Maybe somebody would argue that I will only waste valuable time from the reviewers, but I don't know what else to do in this situation.
Submit your research to a workshop. Workshops are the kind of venue you are looking for: their purpose is to provide feedback on work-in-progress, with a fast review cycle and reviewers focused on a specific area of expertise. 

Submitting your research to a conference may lead to valuable feedback, too, but there's a risk that submitting work-in-progress research can leave behind a poor impression to some of the reviewers. In consequence, these reviewers may be inclined to give rather terse/useless feedback.