Showing papers by "Arun S. Mujumdar published in 1994"
TL;DR: In this paper, a control-volume-based finite-difference method was used to solve the governing mass, momentum, turbulent energy, turbulent kinetic energy dissipation rate, and energy equations iteratively.
55 citations
TL;DR: In this article, a new process is proposed for steam drying; it combines a direct-indirect dryer followed by a direct steam dryer for internal moisture removal, and it is shown that it can be used for drying foods, textiles and sludges.
Abstract: This report reviews some fundamental and practical aspects of steam drying technologies based mainly on studies published in Japan. Steam drying kinetics, and some industrial technologies particularly for drying of foods, textiles and sludges are reviewed with focus on quality of dried material, drying time, dryer selection and energy recovery from steam dryer exhaust. For energy recovery, heat pump technologies are outlined along with characteristics of different types of steam compressors. A new process is proposed for steam drying; it combines a direct-indirect dryer followed by a direct steam dryer for internal moisture removal.
42 citations
TL;DR: In this paper, a control volume-based finite difference method was employed to solve the governing mass, momentum and energy equations for two-dimensional flow field and heat transfer due to laminar heated multiple slot jets discharging normally into a converging confined channel.
30 citations
TL;DR: In this paper, Thompson seedless grapes were initially dried by immersion in a fluidized bed of sugar, and the mass ratio of grapes to sugar was 1:1.5.
Abstract: In order to reduce browning of grapes during drying, a special drying method was developed and evaluated using a laboratory scale fluidized bed dryer. Fresh Thompson seedless grapes were initially dried by immersion in a fluidized bed of sugar. The mass ratio of grapes to sugar was 1:1. The flow rate of hot air (at 45 and 60°C) was sufficient to fluidize the sugar bed, while grapes placed on the screen, 3 cm above the drying air distributor, remained generally stationary. Due to the simultaneous osmotic and convection drying effects, the drying time was reduced by factor ∼1.5 as compared to drying under the similar conditions without added sugar. A special pre-treatment of dipping of grapes in ethyl oleate (2% solution in 0.5% sodium hydroxide) at 80†deg; C for 30 s further reduced the drying time by factor 2 in both cases. The color of osmo-convective dried grapes were comparable to that of sulfur dioxide treated grapes. The texture of osmo-convective dried grapes was more pliable (softer) than ...
25 citations
TL;DR: The behavior of superheated steam and air as drying fluids during the constant rate period of drying paper under impinging jets was compared in the jet temperature range 20 ≤ Tj 465°C for jet Reynolds numbers of l000 ≤ Rej ≤ 12000.
Abstract: The behavior of superheated steam and air as drying fluids during the constant rate period of drying paper under impinging jets was compared in the jet temperature range 20 ≤ Tj 465°C for jet Reynolds numbers of l000 ≤ Rej ≤ 12000. At equal mass flux, steam drying is faster than air drying above the inversion temperature of 175°C. Also, the specific blower power for steam drying is much lower than for air drying at temperatures in the range of industrial importance. Superheated steam impingement drying can therefore lead to important capital investment and energy cost reductions, relative to air drying.
Le comportement de la vapeur surchauffee et de I'air utilises comme fluides de sechage dans la periode de sechage par jets de papier a vitesse constante a ete compare dans la gamme. de temperatures des jets de 20 ≤ T, ≤ 465°C pour des nombres de Reynolds de jets de 1000 ≤ Re, ≤ 12000. A flux massique egal, le sechage a la vapeur est plus rapide que le sechage a I'air au-dessus de la temperature d'inversion de 175°C. En outre, la puissance des ventilateurs pour le sechage a la vapeur est bien inferieure a celle necessaire pour le sechage a I'air dans les gammes de temperatures interessant l'industrie. Le sechage par des jets de vapeur surchauffee peut donc conduire a un investissement en capital moindre et a des reductions des couts d'energie importants, comparativement au sechage a l'air.
16 citations
TL;DR: In this paper, le sechage du papier par des jets de vapeur surchauffee connait une periode de vitesse constante suivie d'une periodes de ralentissement dans une large gamme de conditions operatoires.
Abstract: Le sechage du papier par des jets de vapeur surchauffee connait une periode de vitesse constante suivie d'une periode de ralentissement dans une large gamme de conditions operatoires. La vitesse constante de sechage, etudiee ici dans la gamme de temperatures des jets de 150≤T j , ≤465°C et pour des nombres de Reynolds de jets de 1000≤Re j , ≤12000, est predite avec un ecart de ±12% par l'expression de transfert de chaleur utilisant la correlation de Martin (1977) pour le coefficient de transfert de chaleur corrige pour le transfert de matiere par le facteur d'approximation de l'ecoulement de Couette, et un rapport des proprietes pour tenir compte de la difference de temperature importante entre le jet et le papier
12 citations
TL;DR: In this article, a numerical simulation was carried out to solve the full three dimensional governing equations for steady simultaneously developing laminar flow and heat transfer, and the fluid was considered to be a purely viscous one which followed the power law behavior.
11 citations
8 citations
01 Jan 1994
4 citations
Book•
01 Jan 1994
2 citations
TL;DR: Wicks, Wicks, Jr., F.N. Jones and S.P. Peppas as discussed by the authors reviewed organics coatings in Science and Technology Volume 2: Applications, properties and performance.
Abstract: (1994). Review of:“ORGANIC COATINGS:Science and Technology Volume 2: Applications, Properties and Performance”By Z.W. Wicks, Jr., F.N. Jones and S.P. Peppas Published by John Wiley & Sons, N.Y. 1994, 383 pp. Drying Technology: Vol. 12, No. 7, pp. 1771-1772.