A　large　number　of　fly　ash　particles　in　flue　gas　easily　cause　the　fouling　problem　of　heat　exchangers,　which　seriously　affects　the　efficient　utilization　of　flue　gas　waste　heat.　In　this　study,　experimental　and　numerical　investigations　on　fouling　and　heat　transfer　characteristics　in　cross　flow　heat　exchangers　were　carried　out.　The　on-site　experimental　system　was　established,　and　the　heat　transfer　coefficients　for　different　heat-transfer　surfaces　at　the　fouling　state　were　monitored　in　real　time.　The　weakened　degree　of　heat　transfer　coefficient　and　fouling　thermal　resistance　are　adopted　to　assess　the　effect　of　fouling　on　the　heat　transfer　performance　and　compare　the　practicality　of　four　different　heat-transfer　surfaces　under　dusty　conditions.　Numerical　investigation　was　performed　with　the　fouling　model　established　in　previous　work　to　model　the　thermal-hydraulic　and　fouling　processes.　Numerical　results　are　compared　with　experimental　measurements　and　a　good　agreement　is　achieved.　Results　showed　that　compared　with　the　aligned　circular　tube　bundle,　using　H-type　fins　or　honeycomb　tube　bundle　both　improve　the　anti-fouling　performance,　especially　for　the　honeycomb　H-type　finned　tube　bundle,　which　has　the　lowest　fouling　thermal　resistance.　Therefore,　due　to　the　characteristics　of　easily　soot-blowing　and　lower　fouling　thermal　resistance,　honeycomb　heat　exchangers　are　suitable　for　waste　heat　utilization　of　dusty　flue　gas.　©　2021　Elsevier　Ltd