ISSN:0737-3937    

DOI:10.1080/07373939308916917

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Thirty three sources of hygroscopic data for wheat are identified. Gravimetric methods predominate in the literature, followed by hygrometric methods which largely employ a dew Point technique for relative humidity determination. Hysteresis effects vary considerably in magnitude. The greatest difference between adsorption and desorption isotherms occurs in the 20–40% RH region. A table of equilibrium moisture contents interpolated from the data sets is presented for a Fixed set of temperatures and RH to enable comparison. The isotherm equations used to fit the data are also revewed. The Strohman-Yoerger, Modified-Oswin, Modified-Chung-Pfost, Chen-Clayton and Modified-Henderson equations are identified as the most suitable. Further investigation is needed to compare them.

ISSN:0737-3937    

DOI:10.1080/07373939308916918

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Theories developed for explaining the drying phenomena in grain drying systems are referred to as particular grain drying theories. The objectives of this paper are to review various particular grain drying theories and to suggest directions for future research in this area.

ISSN:0737-3937    

DOI:10.1080/07373939308916919

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

To investigate the performance and feasibility of heat pump assisted microwave drying, a prototype dryer with a heat pump compressor rating of 5 kW and a maximum microwave power of 10 kW, was consrmcted and a mathematical model of the dryer was developed. Extensive drying tests using foam rubber and some vegetables have been conducted using this prototype dryer. The comparison between the experimental and numerical performance data showed good agreement. The influences of the key design and operating parameters have been examined. In panicular, the influence of the applying time of microwave power on the performance of the microwave dryer was shown to be negligible when drying non-hygroscopic materials. The results of the study indicated that with careful design heat pump assisted microwave drying is comparable to conventional convective drying in energy consumption.

ISSN:0737-3937    

DOI:10.1080/07373939308916920

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A finite element model is developed for kiln–drying of refractory concrete castings. Using this model simulations were carried out for concrete castings of different thicknesses to investigate the effects of drying schedules on steam pore pressure. On the basis of the simulation model new drying schedules are proposed.

ISSN:0737-3937    

DOI:10.1080/07373939308916921

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A nonequilibrium distributed parameter model for rotary drying and cooling processes described by a set of partial differitial equations with nonlinear algebraic constraints is developed in this work. These equations arise from the multi–phase heat and mass balances on a typical rotary dryer. A computational algorithm is devekped by employing a polynonial approximation ( orthogonal collocation) with a glotal splinc technique leading to a differential–algebraic equation ( DAE) system. The numerical solution is carried out by using a standard DAE solver.

ISSN:0737-3937    

DOI:10.1080/07373939308916922

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A finite difference scheme for solving the problem of natural transport of heat, mass, momentum and species concentration along vertical porous plates is presented. Several drying related problems are numerically solved, by including a gas-injection boundary condition directly into the governing equations. The effect of variable physical properties is investigated by means of direct comparison against experimental data obtained through holographic interferometry. The relative importance of wall diffusive and convective fluxes is examined. Sherwood and Nusselt numbers can be accurately obtained by means of the proposed techniques.

ISSN:0737-3937    

DOI:10.1080/07373939308916923

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A methodology is presented far obtaining natural convective boundary layer temperature and concentration profiles by means of holographic interferometry. Based on the experimental data obtained from a series of tests involving evaporation from a saturated porous plate, the proposed full, non-similar transport equations were validated altogether with simplified models. The effect of injection velocities (as originated from drying, for instance) is annlyzed. The data and methodology herein proposed should be of value in natural convective drying studies. With minor modifications, the model can be extended to boundary layer analysis of forced convection alang drying plates.

ISSN:0737-3937    

DOI:10.1080/07373939308916924

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Heat and mass transfer rates related to single droplets suspended from a nozzle were studied in a 42mm 1D. horizontal wind tunnel designed to supply hot dry air, to simulate conditions in a spray dryer. A novel rotating glass nozzle facilitated direct measurements of droplet weight and core temperature. Revised correlations were obtained for heat and mass transfer coefficients, for evaporation from pure water drop1ets.

ISSN:0737-3937    

DOI:10.1080/07373939308916925

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Drying studies were carried out on single droplets of gelatin solution, typifying a skin forming, heat-sensitive material. Each droplet was suspended from a novel rotating glass nozzle which enabled direct measurement of its weight and temperature during drying. Observations using this appartatus successfully detected the decrease in core temperature and increase in drying rate resulting from granule dissolution at 30 °C.

ISSN:0737-3937    

DOI:10.1080/07373939308916926

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor