A　flow　sensor　and　two　temperature　sensors　are　included　in　a　traditional　heat　meter.　But　in　heat　exchanger　based　heat　meter,　if　the　temperature　of　water　is　measured,　the　flow　value　can　be　obtained　according　to　the　mathematical　relationship　between　flow　rate　and　water　temperature　at　inlet　and　outlet　of　heat　exchanger.　Thus　the　inaccuracy　of　flowmeter　measurement　caused　by　water　quality　in　the　traditional　heat　meter　can　be　effectively　avoided.　Because　of　the　complexity　of　the　heat　exchanger　structure,　it　is　difficult　to　obtain　the　analytical　solution　between　the　flow　rate　and　the　temperature　of　water.　Such　problem　can　be　effectively　solved　by　CFD　fluid　numerical　simulation.　The　optimum　structure　of　heat　exchanger　can　be　found,　the　relationship　between　flow　rate　and　temperature　of　water　can　be　obtained　and　the　pressure　drop　of　heat　exchanger　is　minimized　through　the　process　of　numerical　simulation　and　Powell　method.　©　2013　IEEE.