Abstract Compared to chemical or synthetic surfactants, biosurfactants have been less explored in heat transfer applications. In the present work heat transfer performance of a biosurfactant (Rhamnolipid) solution in pool boiling experiments has been reported. Pool boiling experiments have been performed on a smooth copper surface with aqueous Rhamnolipid solutions at different concentrations and results have been compared with that of DI water. Surface tension and viscosity of newly developed surfactant solutions have been experimentally measured. Critical micelles concentration (CMC) of aqueous Rhamnolipid solution has been observed at 200 ppm. Significant enhancement of heat transfer coefficient is observed with Rhamnolipid solution at CMC value. It reports 200% enhancement in heat transfer coefficient compared to that with pure water. Active nucleation sites and less coalescence of growing of bubbles contribute for heat transfer enhancement in surfactant solutions. Like other surfactants critical heat flux (CHF) value of Rhamnolipid solution at CMC is observed less than that of pure water. However, reduction in CHF (23%) of present surfactant solution is less than the reduction in CHF (≈50%) of other surfactants. Present Rhamnolipids solution shows better heat transfer performance and higher CHF value compared to SDS surfactant. Moreover, it shows better heat transfer performance in comparison to other biodegradable surfactants reported in the literature.

中文翻译：

---

一种生物表面活性剂作为增强池沸腾传热的前瞻性添加剂

摘要 与化学或合成表面活性剂相比，生物表面活性剂在传热应用中的探索较少。在目前的工作中，生物表面活性剂（鼠李糖脂）溶液在池沸腾实验中的传热性能已有报道。用不同浓度的鼠李糖脂水溶液在光滑的铜表面上进行了池沸腾实验，并将结果与​​去离子水的结果进行了比较。新开发的表面活性剂溶液的表面张力和粘度已通过实验测量。已观察到鼠李糖脂水溶液的临界胶束浓度 (CMC) 为 200 ppm。在 CMC 值下使用鼠李糖脂溶液观察到传热系数显着提高。据报告，与纯水相比，传热系数提高了 200%。活性成核位点和气泡生长的较少聚结有助于表面活性剂溶液中的传热增强。与其他表面活性剂一样，在 CMC 处观察到的鼠李糖脂溶液的临界热通量 (CHF) 值小于纯水的值。然而，现有表面活性剂溶液的 CHF (23%) 减少量小于其他表面活性剂的 CHF (≈50%) 减少量。与 SDS 表面活性剂相比，本发明的鼠李糖脂溶液显示出更好的传热性能和更高的 CHF 值。此外，与文献中报道的其他可生物降解的表面活性剂相比，它显示出更好的传热性能。与其他表面活性剂一样，在 CMC 处观察到的鼠李糖脂溶液的临界热通量 (CHF) 值小于纯水的值。然而，现有表面活性剂溶液的 CHF (23%) 减少量小于其他表面活性剂的 CHF (≈50%) 减少量。与 SDS 表面活性剂相比，本发明的鼠李糖脂溶液显示出更好的传热性能和更高的 CHF 值。此外，与文献中报道的其他可生物降解的表面活性剂相比，它显示出更好的传热性能。与其他表面活性剂一样，在 CMC 处观察到的鼠李糖脂溶液的临界热通量 (CHF) 值小于纯水的值。然而，现有表面活性剂溶液的 CHF (23%) 减少量小于其他表面活性剂的 CHF (≈50%) 减少量。与 SDS 表面活性剂相比，本发明的鼠李糖脂溶液显示出更好的传热性能和更高的 CHF 值。此外，与文献中报道的其他可生物降解的表面活性剂相比，它显示出更好的传热性能。