A　3-D　numerical　simulation　is　performed　on　laminar　heat　transfer　and　flow　characteristics　of　a　slit　fin-and-tube　heat　exchanger　with　longitudinal　vortex　generators.　Heat　transfer　enhancement　of　the　novel　slit　fin　mechanism　is　investigated　by　examining　the　effect　of　the　strips　and　the　longitudinal　vortices.　The　structure　of　the　slit　fin　is　optimized　and　analyzed　with　field　synergy　principle.　The　result　coincides　with　the　guideline　＇front　coarse　and　rear　dense＇.　The　heat　transfer　and　fluid　flow　characteristics　of　the　slit　fin-and-tube　heat　exchanger　with　longitudinal　vortex　generators　are　compared　with　that　of　the　heat　exchanger　with　X-shape　arrangement　slit　fin　and　heat　exchanger　with　rectangular　winglet　longitudinal　vortex　generators.　It　is　found　that　the　Colburn　j-factor　and　friction　factor　f　of　the　novel　heat　exchanger　with　the　novel　slit　fin　is　in　between　them　under　the　same　Reynolds　number,　and　the　factor　j/(f(1/3))　of　the　novel　heat　exchanger　increased　by　15.8%　and　4.2%,　respectively.　(C)　2011　Elsevier　Ltd.　All　rights　reserved.