Rotary regenerator design optimisation and heating surface selection

Swanepoel, D. C. (Daniel Coenraad) (1995)

Thesis (M. Ing.) -- University of Stellenbosch, 1995.

Thesis

ENGLISH ABSTRACT: The rotary regenerator is far from a new device and since its invention more than 70 years ago it has developed into a carefully engineered product. They are mainly used for gas to gas heat transfer and find application in electricity generating plants and in refrigeration and air conditioning systems amongst others. Today the challenge in regenerator design is the optimisation of the operating conditions and the development of improved heating surfaces. The objective of this study is to make a contribution in this respect. The design theory for regenerators is investigated and the dimensionless parameters on which the regenerator effectiveness depends are identified. Approximate solution methods for regenerators are evaluated by comparing their accuracy to more accurate numerical results. The best approximate solutions obtained from the accuracy analysis are used to formulate a regenerator design method. A computer program is written to thermally evaluate or design a rotary regenerator. The program uses either the approximate theory or more accurate numerical methods, depending on user specification. The program can be used to optimise some of the operating conditions. Several new heating surfaces are experimentally tested for their heat transfer and pressure drop characteristics. The performance of the heating surfaces is compared to each other in a specific regenerator application. A cost effectiveness parameter is defined for comparison purposes. It is shown by an example how the matrix rotational speed, the flow split ratio, the matrix wall thickness can be optimised.

AFRIKAANSE OPSOMMING: Die roterende regenerator is allesbehalwe 'n nuwe konsep. Dit is al meer as 70 jaar gelede uitgevind en het sederdien ontwikkel tot 'n gevorderde ingenieursproduk. Dit word uitsluitlik gebruik vir gas tot gas warmteruiling en vind onder andere toepassing in die elektrisiteitsvoorsienings en lugreëling-en-verkoelings bedrywe. Die groot uitdaging vandag in regenerator ontwerp is die optimering van die bedryfstoestande en die ontwikkeling van verbeterde warmteruilingsoppervlaktes. Hierdie studie het ten doel om 'n bydrae op hierdie gebied te maak. Die ontwerpsteorie vir regenerators is ondersoek en daar is uitgewys van watter dimensielose getalle die effektiwiteit afhang. Benaderde oplosteorieë is ondersoek en 'n evaluasie van die akkuraatheid van die teoriee is gedoen deur dit met akkurate numeriese oplossings te vergelyk. 'n Benaderde oplosmetode is geformuleer deur gebruik te maak van die beste benaderde oplossings. 'n Rekenaarprogram vir die ontwerp en evaluasie van 'n regenerator is geskryf. Hierdie program kan beide die benaderde oplosmetode sowel as numeriese metodes hanteer. Die program kan ook gebruik word om van die bedryfstoestande to optimeer. Die warmteoordrag en drukval eienskappe van verskeie nuwe warmteruilingsoppervlaktes is eksperimenteel bepaal. Die vermoë van die oppervlaktes is in 'n spesifieke toepassing met mekaar vergelyk. 'n Kosteeffektiwiteits parameter is vir hierdie doel gedefineer. Daar word aan die hand van 'n voorbeeld geillustreer hoe die rotasie spoed van die matriks, die vloeiverdelingsverhouding, die matriks wanddikte en die keuse van matriks geoptimeer kan word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/58716
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