Yazar "Goksu, Taha Tuna" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    Enhancing the overall thermal performance of a large aperture parabolic trough solar collector using wire coil inserts
    (Elsevier, 2020) Yilmaz, Ibrahim Halil; Mwesigye, Aggrey; Goksu, Taha Tuna
    With the use of large apertures (higher concentration ratios) in parabolic trough solar collectors, increased temperature gradients, increased heat losses and increased heat transfer irreversibilities become inevitable. As such, means of reducing the magnitude of these operating parameters to enhance the overall thermal and thermodynamic performances become crucial. In this study, the use of wire coil inserts in the receiver's absorber tube to improve the parabolic trough solar collector's performance and to lessen the associated temperature gradients is presented. The parabolic trough solar collector having an aperture width of 9 m and a rim angle of 80 degrees was modeled. Using Monte-Carlo ray tracing, the realistic heat flux profile on the receiver's absorber tube was obtained. The resulting non-uniform heat flux profile was later coupled to a finite volume based computational fluid dynamics model. The working fluid properties were considered to be temperature-dependent. The wire coil inserts with a pitch of 0.076, 0.114 and 0.152 m and widths of 0.03, 0.033 and 0.036 m were examined in this study. The wire coil has a triangular cross-section of 0.0076 m in size. Results show significant improvements in receiver thermal performance with the use of wire coil inserts owing to the improved fluid mixing, disruption of the thermal boundary layer and reduction in the absorber tube temperatures. The heat transfer performance is increased up to 183% whereas the thermal efficiency improves between 0.4 and 1.4% when the flow rate is below 13 m(3)/h.
  • [ X ]
    Öğe
    Numerical investigation of the thermo-hydraulic performance of DNA inspired double and triple helix wire coils
    (Elsevier Science Sa, 2022) Goksu, Taha Tuna; Yilmaz, Ibrahim Halil; Behcet, Rasim
    In this study, DNA-inspired wire coil (WC) inserts, namely double wire coil (DWC) and triple wire coil (TWC), were proposed for promoting the thermo-hydraulic performance of a plain tube. Triangular-in-shape WC fitted tubes were modeled in Ansys Workbench and numerically solved in Ansys Fluent. WC inserts with pitches (0.056 m, 0.112 m, 0.168 m), side lengths (0.005 m, 0.006 m) and clearance distances (0.001 m, 0.002 m) were analyzed through a fully developed turbulent flow with the Reynolds number ranging from 6,406-26,647. Detailed model validations were performed using the empirical data and experimental studies in the literature and good agreements were statistically achieved. Results reveal that the proposed inserts can significantly increase the heat transfer performance and performance evaluation criterion (PEC) by almost up to fivefold and 103% compared to those of a plain tube, respectively. DWC increases the PEC by similar to 1.1 times the SWC fitted tube while TWC can increase the PEC by similar to 1.14 times. Increasing the number of WC beyond three would not add benefits to the PEC considerably.