Pumping Power Requirements and Role of Viscosity During Agitation of Concentrated Orange Juice

Author(s):  
M. A. Rao

The rheological behavior of concentrated orange juice (FCOJ) has been shown to be shear-thinning in several recent studies. Concentric cylinder viscometers have been used to obtain the rheological data in these studies. The effect of temperature, soluble solids, and pulp content has been described quantitatively. To estimate the pumping power requirements of FCOJ, the mechanical energy balance equation is used together with the necessary estimates of pressure drop due to friction in pipes and fittings estimated from empirical equations. Empirical equations are available to calculate power consumption during agitation of concentrated orange juice in terms of the dimensionless groups: power and agitator Reynolds numbers for several types of agitators. Paper published with permission.

2012 ◽  
Vol 32 (2) ◽  
pp. 333-341
Author(s):  
Maria E. M. Duarte ◽  
Deyzi S. Gouveia ◽  
Mario E. R. M. C. Mata ◽  
Alexandre J. de M. Queiroz

In this study the rheological behavior in different temperatures (0; 6; 18 e 24 ºC) and physicochemical parameters of integral annona (Annona squamosa) pulp and the annona pulp with milk in different percentages pulp/milk (75g of annona pulp/25g of milk, 50g of annona pulp/50g of milk, 25g of annona pulp/75g of milk) have been availed, in order to verify the effect of temperature and pulp concentration in the rheological behavior of these beverages. To obtain the rheological parameters a concentric cylinder rheometer has been used and the rheograms were analyzed using the Ostwald-de-Wael (power Law) and Herschel-Bulkley models. The physicochemical parameters (sugars, pH, ash, acidity and soluble solids) were determined in order to establish correlations with the rheological behavior. Finally, the best results had been obtained using the Herschel-Bulkley model; the low values for the behavior index (n <1) obtained confirm the pseudoplastic behavior of all samples.


2001 ◽  
Author(s):  
Miles Greiner ◽  
Paul F. Fischer ◽  
Henry Tufo

Abstract The effect of flow rate modulation on low Reynolds number heat transfer enhancement in a transversely grooved passage was numerically simulated using a two-dimensional spectral element technique. Simulations were performed at subcritical Reynolds numbers of Rem = 133 and 267, with 20% and 40% flow rate oscillations. The net pumping power required to modulate the flow was minimized as the forcing frequency approached the predicted natural frequency. However, mixing and heat transfer levels both increased as the natural frequency was approached. Oscillatory forcing in a grooved passage requires two orders of magnitude less pumping power than flat passage systems for the same heat transfer level. Hydrodynamic resonance appears to be an effective method of increasing heat transfer in low Reynolds number systems where pumping power is at a premium, such as micro heat transfer applications.


2017 ◽  
Vol 28 (2) ◽  
pp. 427
Author(s):  
Ricardo David Andrade Pizarro ◽  
Kevin Blanquicett Gónzalez ◽  
Rafael Rangel terraza

The aim of this study was to evaluate the conditions of co-crystallization of bitter orange juice with sucrose on the physicochemical properties of the product. Bitter orange juice was obtained with a mechanical juicer and concentrated on a rotary evaporator. Sucrose syrup 70 oBrix was subjected to heating and stirring of 1000 rpm, until a white color (118 °C) was observed. Bitter orange juice was added to the syrup, and the mixture was subjected to constant stirring of 600 rpm, to observe the formation of a particulate solid material. The co-crystals were dried, grinded and sieved. A dry co-crystal was determined: moisture, bulk density, solubility, water activity and repose angle. High proportion of bitter orange juice added (20%) and low content of soluble solids (50 °Brix) produced co-crystals with low moisture content (2.59%), water activity (0.52) and solubility time (69.4 s). High pH (4.5) of bitter orange juice concentrate produced co-crystals with low moisture contents (1.96%). The co-crystals of bitter orange juice showed good reconstitution characteristics (high solubility); however, these had high humidity (2.5 to 4.5%) and water activity (0.508 to 0.798). 


2008 ◽  
Vol 14 (4) ◽  
pp. 321-328 ◽  
Author(s):  
M. Akbulut ◽  
H. Çoklar ◽  
G. Özen

Rheological parameters of Juniperus drupacea fruit pekmez were evaluated using a rotational viscometer at 10, 20, 30, 40, and 50 °C and at concentrations of 62.8, 68.9, 72.0, and 75.2% total soluble solids. The flow characteristics of Juniperus drupacea fruit pekmez were described by the power law and Herschel—Bulkley models. The Herschel—Bulkley model was found to be the best to describe the rheological property with the coefficient of determination higher than 0.993. Juniperus drupacea pekmez exhibited a time-independent shear thickening behavior. The effect of temperature on viscosity can be described by means of an Arrhenius equation. Depending on the soluble solid contents, the activation energies for flow of diluted samples vary from 78.23 to 60.38 kJ/mol. The effect of soluble solids on viscosity can be described by an exponential equation. Experimental data were fitted to several models in order to describe the effect of temperature and soluble solid content. The combined effect of temperature and soluble solid content on viscosity was also formulated.


1992 ◽  
Vol 32 (8) ◽  
pp. 1141 ◽  
Author(s):  
RA Sarooshi ◽  
RJ Hutton

Juice quality, yield performance, and cropping efficiency of 6 midseason orange varieties (Hamlin, Parramatta, Pineapple, Joppa, White Siletta, and Mediterranean Sweet), together with Seedless Valencia on 4 rootstocks [Troyer citrange, Poncirus trifoliata, rough lemon, and either Benton citrange (coastal) or sweet orange (inland)], were studied for their suitability for both processed and fresh orange juice production. Promising midseason varieties for processed orange juice were Parramatta and Hamlin on Troyer citrange, and Parramatta on P. trifoliata, when grown in coastal districts. Debittered juice of Joppa on Troyer citrange could also be used for processing by early September on the coast. Preferred inland varieties for production of processed orange juice were Mediterranean Sweet and Harnlin on Troyer citrange. Midseason oranges grown inland had higher citric acid levels than the same variety grown on the coast. This resulted in inland fruit having lower ratios of total soluble solids (TSS) to acid, and later maturities, than fruit grown on the coast. Acceptable fresh orange juice was produced from fruit of Parramatta, Hamlin, White Siletta, and Mediterranean Sweet varieties grown on Troyer citrange rootstock in coastal districts; inland, fruit of Mediterranean Sweet, Joppa, Parramatta, and White Siletta varieties on Troyer citrange rootstock produced good quality, fresh orange juice. Hamlin can also be marketed as fresh fruit. In coastal production areas, harvesting can commence from mid July for Hamlin, from mid to late August for Parramata, and from early September for White Siletta and Mediterranean Sweet. Harvest in inland districts for processed juice should commence in mid July for Hamlin and in early September for Mediterranean Sweet, whilst harvest for fresh juice and/or fruit should proceed in early September for Mediterranean Sweet, and in late September for Parramatta, White Siletta, and Joppa. Highest fruit yields and large trees were produced by Parramatta and Joppa on Troyer citrange and rough lemon rootstocks. Most quality characteristics were better for fruit produced on Troyer citrange than on rough lemon. Both Benton citrange and sweet orange performed poorly and are not recommended as rootstocks for midseason oranges. All varieties on Troyer citrange had better yield and TSS/ha than those on P. trifoliata rootstock, which produced smaller but highly cropping efficient trees.


1991 ◽  
Vol 15 ◽  
pp. 63-72
Author(s):  
Robert S. Pritchard

The mechanical energy balance of sea ice provides information about ice dynamic behavior, driving forces and the constitutive law. The energy balance equation, formed as the product of ice velocity with the ice momentum balance equation, describes changes to the kinetic and potential energy densities as power is input to the ice by wind and current. The momentum balance equation may also be used to describe the ice-stress divergence, air stress, and water stress, but the scalar form of the energy balance is simpler to understand. This paper provides new interpretations of several terms in the energy balance equation, in particular power input by air and water stress and by sea-surface tilt. Barometric pressure fields and drifting buoys deployed on the Chukchi Sea ice cover during 1982 provide wind, ice motion and current measurements that allow each term in the energy balance equation to be evaluated as a function of time. Magnitudes of power input by wind and current show how the energy balance is decomposed and help describe the relative importance of these driving forces. In the nearshore Chukchi Sea during February, March and April 1982, both wind and current provided significant forcing of the ice. Ice stress was also important and, at times, dominated other terms in the mechanical energy balance.


Author(s):  
VERA LÚCIA ARROXELAS GALVÃO DE LIMA ◽  
ENAYDE DE ALMEIDA MÉLO ◽  
LUECI DOS SANTOS LIMA

Avaliou-se a qualidade do suco de laranja pasteurizado exposto à comercialização. Amostras refrigeradas e envasadas em embalagens “TetraPak”, coletadas ao acaso, foram adquiridas no mercado varejista da cidade do Recife, durante o período de Setembro/98 a Julho/99. Foram avaliadas 03 marcas comerciais denominadas A, B e C, perfazendo 60 amostras. Para cada marca comercial, as amostras foram adquiridas em duplicata, sendo uma destinada às análises físicoquímicas (vitamina “C”, acidez total titulável, sólidos solúveis totais e pH) e a outra ao teste de incubação (35 ºC durante 10 dias). As marcas analisadas atenderam ao padrão de qualidade estabelecido pelo Ministério da Agricultura, exceto a marca C. Esta apresentou em 70% das amostras analisadas, teor de sólidos solúveis totais (SST) inferior ao padrão e sinais de deterioração durante o teste de incubação em 10% das amostras, evidenciando falhas no processamento térmico. O processamento asséptico associado ao armazenamento sob refrigeração permitiu que todas as amostras das marcas analisadas apresentassem quantidades de vitamina “C” acima do valor mínimo estabelecido pelo Ministério da Agricultura. Abstract The quality of pasteurized orange juice exposed to commercialization was evaluated. Samples, refrigerated and packed in “TetraPak” randomly collected were bought at the retail trade market of Recife, during the period of September/98 to July/99. Three commercial labels named A, B and C were evaluated, making a total of 60 samples. For each commercial label, the samples were acquired in two replicates, one of which was destined to physicochemical analysis (vitamin C, total acidity, total soluble solids and pH) and the other to the incubation test (35 ºC during 10 days). The labels assayed assisted to the established quality pattern of the Ministry of Agriculture, except the C label. This label presented in 70% of the analyzed samples, lower TSS rates than those considered as standard, it also showed signs of deterioration during the incubation test in 10% of the samples, evidencing flaws in the thermal procedure. The aseptic procedure associated to the refrigerated storage allowed all samples of the assayed labels to show vitamin C levels higher than the minimum established by the Ministry of Agriculture.


1934 ◽  
Vol 11 (6) ◽  
pp. 770-779 ◽  
Author(s):  
G. N. Patterson

The motion of air through a channel of small exponential divergence has been investigated experimentally. A flow form derived by Blasius from theoretical considerations has been shown to exist in the range [Formula: see text] for the Reynolds number. The dependence of the general flow form on the initial velocity distribution where the divergence begins has been studied. It has been found that when this initial velocity distribution is parabolic, indicating a laminar motion in the throat of the channel, the flow form is symmetrical. Further investigations have shown that when the initial velocity distribution indicates that the motion near the walls in the throat of the channel lies in the transitional region between a laminar and a turbulent flow, then the flow form is unsymmetrical. Empirical equations have been obtained which give (1) the initial velocity distribution in the transitional region at R = 75.1, and (2) the motion near the walls where the divergence begins for Reynolds numbers lying in the range [Formula: see text].


Author(s):  
Jeffrey M. Aristoff ◽  
Howard A. Stone

We consider the influence of aerodynamic forces on the shape of a whirling filament that is held at both ends, i.e. a jump rope. At high Reynolds numbers, the rope curls out of the plane and towards the axis of rotation—a feature we demonstrate via experiment. We derive a pair of coupled nonlinear differential equations that characterize the steady-state shape of the rope, and the resulting eigenvalue problem is solved numerically. The solution depends on two dimensionless groups: the ratio between the length of the rope and the distance between its ends, and the relative magnitude of the aerodynamic to centrifugal forces. As the latter ratio is progressively increased, the tension in the rope and the out-of-plane deflection increases, until eventually the rope reaches a limiting shape. Finally, we show that the airflow-induced shape change leads to a relative reduction in drag and has implications for successful skipping.


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