Due to the tightly-coupled hardware and software architecture of existing RAN systems and their non-flexibility, disaggregation of software and hardware can bring many unprecedented opportunities regarding enabling the entrance of multiple small-scale infrastructure providers to enter the RAN market, which creates more competitive and innovative RAN ecosystem. Moreover, mobile network operators (MNOs) will also have the advantage of selecting the services according to their network requirements. Open Radio Access Network (O-RAN) builds a multi-vendor RAN ecosystem and utilizes openness and intelligence to address the complexity of network functionalities, increase development agility, and provide more cost-effective platforms due to softwarization and the avoidance of dedicated hardware. However, O-RAN faces many challenges, such as interoperability, convergence, and AI/ML management which still need to be addressed before its wide deployment. This paper surveys the existing issues in the Open RAN ecosystem and explores existing solutions.
This computational fluid dynamics (CFD) based study aims to examine the heat transfer performance of Al2O3 based nanofluid compared to that of base fluid (60:40 volume/volume mixtures of ethylene glycol and water). Geometrical model of flat tube of a vehicle radiator was designed to conduct a comparative study using single-phase and Eulerian multi-phase CFD approach. Heat transfer performance parameters such as Nusselt number and surface heat transfer coefficient were evaluated by changing volumetric concentration, inlet velocity, inlet temperature and particle size of the nanoparticles. It was observed that for 2% volume concentration of Al2O3, the Nusselt number increased by two times compared to that of the base fluid. Increase in volume concentration (0.1 to 3%) showed an increase in skin-friction coefficient, pressure drop across the tube, and pumping power required. With the increase in Reynolds number (700 to 5500), the increase in Nusselt number, as well as surface heat transfer coefficient was almost linear for both laminar and turbulent flow regimes. Variation of particle sizes (10, 25, 40 and 60 nm) showed maximum thermal performance at 25 nm. These observations illustrate the superior heat transfer performance of Al2O3 based nanofluids which calls for their potential application in heat exchangers such as vehicle radiators by replacing conventional coolants.
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