Steam-side irreversible loss analysis of spirally corrugated tube

As a mean for heat transfer enhancement, the utilization of spirally corrugated tubes (SCT) will inevitably bring about irreversible loss. Apart from pressure drop, the quantitative analysis of the available energy loss is also an effective evaluation criterion, which is assessed from the perspective of the second law of thermodynamics. This paper presents the concept of thermal exergy loss number to quantify the available energy loss stemming from temperature difference. Meanwhile, the influence of structural parameters on irreversible loss is also investigated for SCT. The results shows that mechanical exergy losses in the near-wall region of spirally corrugated tubes are relatively substantial. Heat transfer enhancement can be effectively improved by increasing the corrugation depth and decreasing the pitch, together with consequent incremental irreversible loss in the flow. Moreover, Response Surface Methodology (RSM) is used to visualize the effects of structural parameters on exergy losses. According to numerical results, the corrugation pitch ratio plays a significant role in irreversible loss during the heat transfer process. The fluid in the SCT with pitch ratio 0.4 and depth ratio 0.125 has the least available energy losses due to temperature difference, and the corresponding thermal exergy losses reach the minimum value.