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Effect of guar gum on the physicochemical, thermal, rheological and textural pr...

In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar...

Friction factors of power-law fluids in chevron-type plate heat exchangers

In the present work laminar flows of Newtonian and power-law fluids through cross-corrugated chevron-type plate heat exchangers (PHEs) are numerically studied in terms of the geometry of the channels. The plates area enlargement factor was a typical one (1.17), the corrugation angle, β, varied between 30° and 60° and the flow index behaviour, n, between 0.25 and 1. Single friction curves fReg = K for both Newto...

Heat transfer to Newtonian and non-Newtonian fluids in cross-corrugated chevron...

Food fluids are frequently processed in plate heat exchangers (PHEs) and usually behave as non-Newtonian fluids, this behaviour being scarcely considered for PHEs design purposes. Moreover, many food fluids processed in PHEs have a high viscosity and, therefore, data obtained in laminar flow regime is useful to practical applications. The thermal-hydraulic performance of PHEs is strongly dependent on the physic...

New plates for different types of plate heat exchangers

The first patent for a plate heat exchanger was granted in 1878 to Albretch Dracke, a German inventor. The commercial embodiment of these equipments has become available in 1923. However, the plate heat exchanger development race began in the 1930’s and these gasketed plate and frame heat exchangers were mainly used as pasteurizers (e.g. for milk and beer). Industrial plate heat exchangers were introduced in th...

Finite-element solutions for laminar flow in sinusoidal corrugated-plate channels

Heat transfer to Newtonian and non-Newtonian fluids in cross-corrugated chevron...

Research on heat transfer of fluids during thermal processing is useful to optimise the heat exchanger design, as well as to define quality levels of processed fluids. In this study, nonisothermal fully developed laminar flows of distinct fluids in different PHEs passages (main heat transfer area) were numerically studied, in order to evaluate the influence of the geometrical properties of the PHE channels and ...

Heat transfer to newtonian and non-newtonian fluids in cross-corrugated chevron...

Laminar flow in chevron-type plate heat exchangers: CFD analysis of tortuosity,...

Liquid foodstuffs with high viscosity are usually processed in plate heat exchangers (PHEs) at laminar or low Reynolds numbers, Re, flows. The tortuosity coefficient is used by the manufacturers for the design and optimization of PHE geometries. Using the finite-element computational fluid dynamics program POLYFLOW®, fully developed laminar flows in double-sine chevron-type PHEs passages are analysed in this wo...

CFD aplicada ao estudo de permutadores de calor de placas chevron

Os fluidos alimentares com viscosidade elevada são frequentemente processados em permutadores de calor de placas (PCPs) em regime laminar. O desempenho termo-hidráulico dos PCPs do tipo chevron depende das características geométricas dos mesmos, nomeadamente do ângulo das corrugações sinusoidais das placas, do espaçamento entre placas e do factor de incremento de área, definido como a razão entre a área real da...

Tortuosidade em permutadores de calor placas

Afectar ao Departamento de Tecnologia Química e Biológica - Docente Ricardo Dias e ao docente Carlos Balsa do Departamento de Matemática ; Utilizando o software comercial de mecânica de fluidos computacional POLYFLOW® estudou-se o escoamento laminar isotérmico de um fluido Newtoniano com propriedades físicas constantes no interior de canais de permutadores de calor de placas corrugadas. Foi estudada a dependên...