![Sample our Economics, Finance,Business & Industry journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5931/TOC-Subject-Sample-2021-Economics-Finance-Business-Industry.jpg"})
ABSTRACT
In this present study, the performance of a newly modified solar collector named trapezoidal-trough solar collector (Tra-trough) has been examined using peripherally wing-cut swirl generator (PSG). The experiment has been executed at Government College of Engineering, Salem, Tamilnadu, India (Latitude: 11°66´N and Longitude: 78°15´E) with three different wing shapes including PSG with triangular wings (PSG-Tri), rectangular wings (PSG-Rec) and trapezoidal wings (PSG-Tra). The obtained results are contrasted with plain tube Tra-trough (TT-plain) solar collector under the same working condition. The experimental trials are made by keeping swirl ratio (Y = 3), wing-span ratio (b/W = 0.3) and wing-chord ratio (d/W = 0.4) as constant. The results obtained from the TT-plain are verified with the fundamental equations and found the deviations within ±11.21% for Nusselt number and ±8.24% for friction factor. From the experimental result, the PSG provides higher heat transfer rate over the TT-plain with/without typical swirl generator (TSG). The results also exposed that the PSG with trapezoidal wings (PSG-Tra) offers higher heat transfer rate and thermal efficiency than those given by other type of wing shapes. The thermal performance of trapezoidal wings (PSG-Tra) is enhanced up to 137% over the TT-plain. In addition, correlations for predicting the Nusselt number and friction factor have been developed. The deficiency of the predicted value for Nusselt number and friction factor are within ±10.31% and ±11.21%, respectively.
Nomenclature
| Ac | = | Collector aperture area, m2 |
| A | = | Surface area of riser tube, m2 |
| Cp | = | Specific heat kJ/kg °C |
| D | = | Diameter of riser tube, m |
| F | = | Friction factor, (dimensionless) |
| Ht | = | Solar irradiation intensity, W/m2oC |
| FR | = | Heat removal factor (dimensionless) |
| k | = | Thermal conductivity, W/m°C |
| L | = | Riser tube length, m |
| M | = | Mass flow rate, kg/s |
| Nu | = | Nusselt number, dimensionless |
| ΔP | = | pressure drop of water (N/m2) |
| Pr | = | Prandtl number, dimensionless |
| Q | = | Heat transfer rate, W |
| Re | = | Reynolds number, dimensionless |
| Tm | = | Bulk mean temperature of fluid in the riser tube, °C |
| T | = | Temperature, °C |
| U | = | overall heat transfer co-efficient (W/m2K) |
| Ul | = | overall heat loss co-efficient (W/m2K) |
| Y | = | swirl ratio (length of one twist/diameter of the twist) (dimensionless) |
| Greeks | = | |
| Ρ | = | density of water (kg/m3) |
| µ | = | dynamic viscosity of water at bulk mean temperature (Ns/m2) |
| µw | = | dynamic viscosity at wall temperature (Ns/m2) |
| τα | = | product of transmittance-absorptance |
| η | = | thermal efficiency,% |
| Subscripts | = | |
| a | = | ambient |
| i | = | inside |
| o | = | outside |
| P | = | plain |
| s | = | swirl flow/turbulator |
| in | = | inlet |
| out | = | outlet |
Supplementary material
Supplemental data for this article can be accessed on the publisher’s website.