Forced convection heat transfer and friction characteristics in multi-exit -rectangular package with inclined tube bundles

An experiment was carried out to investigate the characteristics of the heat transfer and pressure drop for forced convection airflow over tube bundles that are inclined relative to the on-coming flow in a rectangular package with one outlet and two inlets. The experiments included a wide range of angles of attack and were extended over a Reynolds number range from about 250 to 12,500. Correlations for the Nusselt number and pressure drop factor are reported and discussed. As a result, it was found that at a fixed Re, for the tube bundles with attack angle of 45 ° has the best heat transfer coefficient, followed by 60, 75 and 90 °, respectively. This investigation also introduces the factors % MathType!Translator!2!1!AMS LaTeX.tdl!TeX -- AMS-LaTeX! % MathType!MTEF!2!1!+- % feaafiart1ev1aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcqyaaaaaaaaWqVb % xEG8MzGieBHn2Aa8qabaWaaeWaaeaacaWGdbWaaSbaaSqaaiabeI7a % XbqabaGccqGH9aqpdaWcgaqaamaanaaabaGaaeOtaiaabwhaaaWaaS % baaSqaaiabeI7aXbqabaaakeaadaqdaaqaaiaab6eacaqG1baaamaa % BaaaleaacqaH4oqCcqGH9aqpcaaI5aGaaGimamaaCaaameqabaGaeS % igI8gaaaWcbeaaaaGccaaMf8Uaaeyyaiaab6gacaqGKbGaaGzbVlaa % doeadaqhaaWcbaGaeqiUdehabaGaai4jaaaakiabg2da9maalyaaba % GaaeyraiaabwhadaWgaaWcbaGaeqiUdehabeaaaOqaaiaabweacaqG % 1bWaaSbaaSqaaiabeI7aXjabg2da9iaaiMdacaaIWaWaaWbaaWqabe % aacqWIyiYBaaaaleqaaaaaaOGaayjkaiaawMcaaiaacYcaaaa!61CE! $$\left( {C_\theta = {{\overline {{\text{Nu}}} _\theta } \mathord{\left/ {\vphantom {{\overline {{\text{Nu}}} _\theta } {\overline {{\text{Nu}}} _{\theta = 90^ \circ } }}} \right. \kern-\nulldelimiterspace} {\overline {{\text{Nu}}} _{\theta = 90^ \circ } }}\quad {\text{and}}\quad C_\theta ^\prime = {{{\text{Eu}}_\theta } \mathord{\left/ {\vphantom {{{\text{Eu}}_\theta } {{\text{Eu}}_{\theta = 90^ \circ } }}} \right. \kern-\nulldelimiterspace} {{\text{Eu}}_{\theta = 90^ \circ } }}} \right),$$ which can be used for finding the heat transfer and the pressure drop factor on the tube bundles positioned at different angles to the flow direction. Moreover, no perceptible dependence of Cθand C′θ on Re was detected. In addition, flow visualizations were explored to broaden our fundamental understanding of the heat transfer for the present study.