DEPARTMENT OF MECHANICAL ENGINEERING

Permanent URI for this communityhttps://repository.ui.edu.ng/handle/123456789/476

Browse

Subject: search.filters.subject.Heat transfer coefficient

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Numerical modelling of effect of baffle orientation offset on shell-and-tube heat exchanger performance
    (2018-02) Petinrin, M. O.; Dare, A. A.
    The performance of a shell-and-tube heat exchanger (STHE) is largely dependent on the type, orientation and offset arrangement of the baffles employed. In this paper, the thermal-hydraulic characteristics of STHEs with 90°, 120° and 180° offset arrangements of baffles were studied numerically. The study was performed on 19-tube and 31-tube heat exchangers, and also for three shell-side working fluids: air, water and engine oil. The numerical analyses were carried out using the k-ε model with imposed realizability constraint, and were solved with COMSOL Multiphysics. The STHE with 180° had higher pressure drop than other STHEs for all the ranges of mass flow rate. STHE with 120° showed better performance for shell-side heat transfer coefficient at the same pressure drop while STHE with 90° had much higher performance factor at the same mass flow rate. It is concluded that baffle offset arrangements significantly affected the shell and tube heat exchanger performance.
  • Thumbnail Image
    Item
    Experimental study of flow and heat transfer in rectangular ducts with ribbed surfaces
    (2022) Petinrin, M. O.; Ajuka, L. O.; Adebayo, A. S.; Oderinlo, O. U.
    The Pivotal focus on fluid and thermal equipment performance have remained to directly lower energy cost by utilizing varieties of surface structures including extended surfaces, treated surfaces, and rough surfaces. This has necessitated the resurgence of surfaces with dimples and protrusions for an enhanced system efficiency in electronic components, gas turbine blade cooling, vortex creation on air foil structures, combustion chambers, printed circuit boards, microfluidic passageways, and heat exchangers features. In this study, the performance characteristics, heat transfer enhancement (Nu/Nuo), friction factor ratio (f/fo), and overall thermal performance (OTP) of two test channels with distinct surface structures. The performance parameters were evaluated using experimental rigs, one with continuous spiral rib channel and the other one with discontinuous spiral rib channel. Thereafter, the results from both test channels were compared to a smooth surface channel. Comparing the performance characteristics, Nu/Nuo, f/fo, and OTP of the discontinuous spiral rib and continuous spiral rib were 31.5%, 91.3%, 4.4% and 81.9%, 113.6%, 38.4% higher than the smooth surface spiral rib channel. Finally, the study shows that the continuous spiral rib channel gave a lower pressure loss, and was established to possess higher heat transfer coefficient and overall thermal performance than the discontinuous spiral rib channel.