Few questions regarding heat

how much heat does a 400 watt hps generate and how much heat does a 250 watt HPS generate is it possible to run them in a clost with just a fan blowing on the bulb the closet is 2X7X7 roughly also would a 250 watt be enough light for like 10 plants?

A fan blowing won't do anything at all to cool, but rather just move the same hot air all around the cabinet. You need to think along the lines in intake and exhaust.