非牛顿纳米流体在螺旋隔板翅片管换热器与弓形隔板光滑管换热器壳程的换热性能对比

Comparison on Heat Transfer Performance of non-Newtonian Nanofluids in Shell Side of Heat Exchangers With Different Types of Baffles

选用黄原胶作为非牛顿流体基液,碳纳米管为纳米添加粒子,实验研究了非牛顿纳米流体及其基液在螺旋隔板翅片管换热器和弓形隔板光滑管换热器的壳程冷却传热性能。实验结果表明,两台换热器的对流传热系数和压降均随雷诺数的升高而升高。与基液相比,非牛顿纳米流体在螺旋隔板翅片管换热器和弓形隔板光滑管换热器中的壳程传热系数分别提高31.3%和18.3%,其压降分别增大36.1%～52.6%和35.6%～41.4%。在雷诺数相同时,非牛顿纳米流体在螺旋隔板翅片管换热器的综合热性能为弓形隔板光滑管换热器的2.78～2.93倍。

A certain amount of XG was dissolved into deionized water as basefluid,followed by adding the obtained solution into the suspension of MWCNTs as non-Newtonian Nanofluids.The heat transfer performance of non-Newtonian Nanofluids and basefluid in the shell side of helical baffle heat exchanger with low-finned tubes and segmental baffle heat exchanger with smooth tubes were experimentally measured.It can be found that both of the convective heat transfer coefficient and pressure drop of the tested fluids in these two tested heat exchangers increase with the increase of Reynolds number,and compared with the non-Newtonian basefluid,the convective heat transfer coefficients of non-Newtonian nanofluids in helical baffle heat exchanger and segmental baffle heat exchanger increase by 31.3%and 18.3%respectively,while the pressure drops of non-Newtonian nanofluids increase by 36.1%~52.6%and 35.6%~41.4%respectively.In addition,at the same Reynolds number,the integrated thermal performance of helical baffle heat exchanger with low-finned tubes is 2.78-2.93 times of that of segmental baffle heat exchanger with smooth tubes.