英语翻译As previously mentioned,the common problem withreducing the transverse spacing in order to increase heattransfer surface area is that the flow passage area alsodecreases resulting in increased pressure drop and blockageof the heat exchang

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英语翻译As previously mentioned,the common problem withreducing the transverse spacing in order to increase heattransfer surface area is that the flow passage area alsodecreases resulting in increased pressure drop and blockageof the heat exchang

英语翻译As previously mentioned,the common problem withreducing the transverse spacing in order to increase heattransfer surface area is that the flow passage area alsodecreases resulting in increased pressure drop and blockageof the heat exchang
英语翻译
As previously mentioned,the common problem with
reducing the transverse spacing in order to increase heat
transfer surface area is that the flow passage area also
decreases resulting in increased pressure drop and blockage
of the heat exchanger due to deposit build up between
the closely spaced tube rows.Fig.8 shows how
the five tube bundle arrangements numerically investigated
perform in terms of deposition rate and deposition
rate distribution between the tube rows.Comparing the
arrangements at the larger transverse spacing,it is evident
that the streamlined tube shapes of the elliptic
and the DDEFORM tubes lead to a reduction in the
overall deposition rate,which is most evident in the
downstream tube rows,although even the first row
shows a reduction in the order of 30–50%.However,
as shown previously,at the large transverse spacing
the benefits with regards to both heat transfer rate and
pressure drop are not favourable.On the other hand,
by looking at the closely spaced arrays,it can be seen
that the deposition rates are still at 26% and 44% of
those of the standard arrangement with circular crosssectional
tubes but heat transfer is significantly higher
(see Fig.6) and pressure drop lower (see Fig.7).The
DDEFORM tube shows a superior performance over
the elliptic one in terms of deposition rates.The different
behaviour of the bundles with non-circular tubes is further
explored in the next section
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英语翻译As previously mentioned,the common problem withreducing the transverse spacing in order to increase heattransfer surface area is that the flow passage area alsodecreases resulting in increased pressure drop and blockageof the heat exchang
如前所述,为了增加传热表面积而减小横向间隔的共同问题是由于沉淀堆积在靠近的管道列之间液流通道面积减少导致压力下降和热交换器堵塞.图8所示,由在数字调查而来的五组管束排列在管束列之间如何依据沉淀比率和沉淀比率分配运行.
比较以宽大横向间隔方式的排列,显而易见,椭圆形的和异形管的流线型管导致在整个沉淀率上的减少,尽管甚至第一根管道显示以30–50%顺序的减少,但是这一点在下游管束列中更为明显.无论如何,如前面所显示,以宽大横向间隔的方式兼顾传热比率和压力下降两个方面的效益是不利的.
另一方面,通过观察靠近间隔的编组排列,可以发现沉淀率在那些具有圆形代表性管道的标准排列中依然是26% 和44%,但是热传导值得注目的是较高(见图6)而且压力下降较低(见图7).异形管道显示出的高性能在沉淀率方面超过椭圆形管道.以非圆形管捆扎管束的不同的运转状况将在下一个章节中研究.

如前所述,减小横向间距以增加传热面积的常见问题是,流向管面积也被减小了,而设置过度密集的管道之间会形成沉积,导致压力降增加和热交换器堵塞。 图8说明如何根据沉积率和管道之间沉积分布通过数字来研究五条管道布置的性能。非常明显,与大横向间距布置相比,对椭圆和异形管道进行流线型布置能减少总的沉积率,这对下游管道的作用非常明显,第一排管道的沉积率也减少了30%-50%。
但是,如前所示,如果设置...

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如前所述,减小横向间距以增加传热面积的常见问题是,流向管面积也被减小了,而设置过度密集的管道之间会形成沉积,导致压力降增加和热交换器堵塞。 图8说明如何根据沉积率和管道之间沉积分布通过数字来研究五条管道布置的性能。非常明显,与大横向间距布置相比,对椭圆和异形管道进行流线型布置能减少总的沉积率,这对下游管道的作用非常明显,第一排管道的沉积率也减少了30%-50%。
但是,如前所示,如果设置大的横向间距,热传递率和压力降的效果都不理想。 而另一方面,观察密集排列布置,可以看到沉积率仍然高达循环交叉标准布置的26%和44%,而热传递却大大提高(见图6),压力降降低(见图7)。异形管的沉积率性能优于椭圆形管。 下一节将详细说明非循环管道的不同性能。

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