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The miniaturisation of systems has widely attracted researchers to contribute to the thermal performance enhancement utilising efficient heat transfer devices. Pulsating heat pipe (PHP) is an inimitable passive two-phase energy conversion/transport device capable of transferring extensive heat energy by oscillating liquid slugs and vapour plugs from hot to cold areas suitable for the management of generation of heat in electronics. Several theoretical, experimental and visualisation studies are made on PHP to understand operational mechanisms and to arrive at optimal conditions. Although PHP has potential application in the field of heat management, its effective utilisation is limited due to complex operational mechanisms.It is observed that PHPs are effective and reliable devices for utilisation in numerous energy systems. It is observed that PHPs are effective and reliable devices for utilisation in numerous energy systems. Advanced research is directed towards numerical simulations on the evaluation of PHP performance with non-conventional working fluids. It is found that the use of ternary hybrid nanofluid in PHP has scope for research work. The objective of this paper is to review the existing methodologies for enhancing the PHP overall performance and its applications. [ABSTRACT FROM AUTHOR]

The purpose of this research is to demonstrate the use of a new and highly efficient population-based algorithm, known as Heat Transfer Search (HTS), for optimisation of an active magnetic bearing (AMB) system. In this research paper, the HTS algorithm is employed to minimise the overall bearing volume, considering turns per pole pair, the maximum required current, pole width, and coil length as the design variables. Constraints are imposed on the maximum flux density, current density, winding space, and maximum magneto-motive force. It is found that, for the operating conditions considered herein, the Heat Transfer Search algorithm yields around 23% lower bearing volume as compared to that obtained using more popular optimisation techniques such as Genetic Algorithms (GA) and Pattern Search (PS). Finally, a comparative study on the impact of magnetic core material presented herein reveals that Supermendur yields the best results. This is the first attempt to integrate the impact of magnetic core material on the optimisation of the AMB system. [ABSTRACT FROM AUTHOR]

Heat exchangers have found extensive applications in the engineering sector owing to the crucial need for heat transfer and temperature regulation in the process industry. The performance analysis of a heat exchanger can either be investigated experimentally or utilizing computational fluid dynamics (CFD). The simulation of flow conditions based on CFD principles is considered as a contemporary approach for conducting performance analysis and design optimization of the heat exchanger. The paper aims to present how the performance optimization parameters of shell and tube heat exchanger effect its performance in terms of the extent of heat transfer achieved and fall in the shell outlet temperature. A standard model (Model 1) was initially defined, and seven subsequent models were created with one varying parameter as compared to Model 1 to carry out the comparative analysis. The results showed that decrease in inlet velocity, increase in thermal conductivity of the heat exchanger material, reduction in baffle spacing and use of triangular tube bundle arrangement has significant influence on the reduction of the condensate temperature. The effects of the same parameters on the temperature distribution and heat transfer rate have also been discussed. [ABSTRACT FROM AUTHOR]

This paper presents the effects of aspect ratio (0.1 ≤ A R ≤ 0.7) , Rayleigh number ( 10 2 ≤ R a ≤ 10 6 ) and inclination angle 0 ° ≤ γ ≤ 90 ° of the heated rectangular cylinder on heat transfer and fluid flow characteristics due to natural convection in air around heated rectangular cylinders of different sizes inside a cold square enclosure. Galerkin finite element method was adopted for the solution of the developed model. The walls of the enclosure were maintained at an isothermal cold temperature while the boundaries of the rectangular cylinder were kept at a constant hot temperature. The results are presented in the form of isothermal contours, stream functions, local and average Nusselt numbers. It has been found that for the range of aspect ratio and Rayleigh number considered, the rate of heat transfer increases with increasing aspect ratio and Rayleigh number. Furthermore, the orientation angle of the rectangular cylinder was found to generally augment heat transfer rate except at A R value of 0.1 , where the average Nusselt number declines beyond γ = 45 ° for all the range of Rayleigh numbers considered. Results from the present study could be applied to nuclear reactor technology and cooling of electronic chips system optimisation. [ABSTRACT FROM AUTHOR]

As rail operators look for efficiency improvement, a new trend towards integration of detection technologies on revenue raising rolling stock has emerged, the objective being that a saving can be made by eliminating specialised rolling stock and reducing network scheduling. An area currently attracting research attention in the Australian heavy haul segment is the detection of rail foot flaws from moving vehicles through the use of Infrared Thermography. This paper presents a modelling and simulation methodology for full train simulation using a co-simulation approach for calculating heat transfer in the rail under a number of different vehicle system dynamics cases. The excitation source for the heat transfer focuses only on wheel/rail contact mechanics. The paper will explore the problem from a Modulated Thermography perspective that uses periodic heating and observation of the heating process for flaw detection. [ABSTRACT FROM AUTHOR]

The objective of this paper is to study and analyse heat losses from the absorber tube of a parabolic trough solar collector (PTSC) system and development of heat loss correlation. Computational fluid dynamics has been employed to obtain the convective and radiative heat losses. Heat loss model is simulated by employing the discrete ordinate (DO) radiation model to account for the radiation exchange in an enclosure between steel tube and glass cover, which is maintained as vacuum. Heat losses from the glass cover due to forced convection and radiation have been modelled and simulated. The effect of different emissivity on the absorber tube, different diameter ratio between absorber tube and glass cover, different heat transfer coefficients due to wind effects are studied in the considered PTSC system. Results are mentioned in dimensionless numbers for wider applicability. The result indicates that by varying the emissivity of the tube wall from 0.2 to 0.8, Nusselt number increases from 5.66 to 18.6. Similarly, when the heat transfer coefficient is changed from 6.89 to 19.49 W/m2K, Nusselt number increased from 5.66 to 5.81. Effect of vacuum has been studied as well. Finally, the correlation between Nusselt number and its influencing parameters has been obtained for the PTSC. [ABSTRACT FROM AUTHOR]

Vacuum glazing is an innovative transparent thermal insulator that has applications in high performance windows. Two sheets of glass are separated by an evacuated space maintained by a regular array of support pillars, and the structure is sealed around the edges with solder glass or a metal bond. The evacuated internal gap reduces the heat transfer across the glazing by eliminating air conduction and convection between the glass sheets. This review paper traces the development of vacuum glazing from the initial proposal 100 years ago, to the fi rst reported manufacture in 1989 by the University of Sydney, the subsequent commercialisation of that design in 1996 and recent advances. The various design challenges are discussed along with the innovative ways they were successfully addressed by two research groups. Several key non-technical factors that have been equally important to the commercialisation and acceptance of this new technology are also presented. The future prospects for vacuum glazing are discussed in the context of the growing interest in energy effi cient buildings and higher standards for the thermal performance of windows. [ABSTRACT FROM AUTHOR]