In this investigation, the influence of the non-circular type of holes in perforated delta-winglets on the thermo-hydraulic performance is studied. The copper strip having perforated delta-winglets attached on both sides (top and bottom) is inserted into the absorber tube of the solar water heating system. Distinct parameters of the perforated delta-winglets which are varied in present investigation are Circularity (${\psi }_{pw}$), Pitch ratio ($P_{pw}$), Angle of attack $\left({\alpha }_{pw}\right)$, Spacer length ($S_{pw}$) and the Reynolds number $\left(Re\right)$. The circularity (${\psi }_{pw}$ ) varies from 1.0 to 0.75, Pitch ratio ($P_{pw}$) varies from 2.0 to 0.5, Angle of attack $\left({\alpha }_{pw}\right)$ varies from ${15}^o$ to ${60}^o$, Spacer length ($S_{pw}$) varies from 0 to 450 mm and the Reynolds number $\left(Re\right)$ of the flow varies between 200 and 1200. The experimental examination shows that the high non-circularity of perforation holes causes maximum thermal enhancement of Nusselt number ($N{u}_{pw}$), while perfectly circular type of perforation holes in delta winglets have considerable lower impact on the thermal enhancement of $N{u}_{pw}$. The experimental outcomes show that the perforated delta-winglets with Circularity ${\psi }_{pw}$ = 0.86, Pitch ratio $P_{pw}$ = 0.5, Angle of attack ${\alpha }_{pw}$ = ${45}^0$ and Spacer length $S_{pw}$ = 0 mm have optimum influence on $N{u}_{pw}$ and friction factor ($f_{pw}$) of the solar water heating system.

在这项研究中，研究了带孔三角翼小孔中非圆形孔洞对热工液压性能的影响。在两侧（顶部和底部）连接有穿孔三角形小翼的铜条插入太阳能热水系统的吸收器管中。在当前研究中变化的带孔三角翼小翼的不同参数是圆度（${\psi }_{pw}$），螺距比（$P_{pw}$），迎角 $（{\alpha }_{pw}）$，垫片长度（${\mathrm{小号}}_{pw}$）和雷诺数 $（\mathrm{[R}Ë）$。圆度（${\psi }_{pw}$ ）介于1.0到0.75之间，音高比（$P_{pw}$）从2.0到0.5不等，迎角 $（{\alpha }_{pw}）$ 从 ${15}^{Ø}$ 至 ${60}^{Ø}$，垫片长度（${\mathrm{小号}}_{pw}$）从0到450毫米不等，雷诺数 $（\mathrm{[R}Ë）$ 流量的变化在200到1200之间变化。实验检查表明，穿孔的非圆形度很高，导致Nusselt数（$ñ{ü}_{pw}$），而三角形小翼上的完美圆形穿孔眼对热增强的影响较小 $ñ{ü}_{pw}$。实验结果表明，带圆形度的穿孔三角翼小翼${\psi }_{pw}$ = 0.86，螺距比 $P_{pw}$ = 0.5，迎角 ${\alpha }_{pw}$ = ${45}^0$ 和垫片长度 ${\mathrm{小号}}_{pw}$ = 0 mm对 $ñ{ü}_{pw}$ 和摩擦系数（$F_{pw}$）的太阳能热水系统。