摘要:

ABSTRACTThe residence time distribution (RTD) studies were conducted to predict the flow characteristics in thin film SSHE. the experiments were conducted at zero heat flux using water as working fluid. A pulse input in form of saturated sodium chloride solution was used as the disturbance at inlet and the response in form of electrical conductivity was measured at outlet. Thirty‐two trials were conducted at different flow rates, number of blades and rotor speeds. the E‐curves were plotted. It was inferred that the flow in thin film SSHE approximates to plug flow. Also, as the mass flow rate increased, RTD improved. the increasing number of blades resulted in appreciable improvement in RTD. the rotor speed had similar effect as that of number of blades on RTD. However, the number of blades had more profound effect as compared to rotor speed. If the rotor design is modified then RTD can be improved and simultaneously the power consumption can be kept at mini

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1988.tb00005.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTA simple model is proposed to estimate freezing times of foodstuffs of simple geometrical shapes (infinite flat slabs, infinite cylinders, spheres, rectangular parallelepipeds and finite cylinders). This model combines Plank's equation for change of phase period with the unsteady heat transfer solutions for cooling periods before and after phase change.The total freezing time is obtained by the determination and the summation of the precooling, phase change and tempering times. the results produced are at least as accurate as or better than any of the previous methods, including regression formula and finite difference computations.Tables required for fast and accurate predictions of freezing times of foodstuffs with this method are provided.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1988.tb00006.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTThe information of thermal conductivity of milk is required for the design of heat exchanger equipment in the dairy processing. Thermal conductivity of whole milk was experimentally determined by a steady‐state, parallel disk, relative method at various concentrations (from 37 to 72.4% total solids) and temperature range between 40 to 90°C. This thermal property of milk increased with rise in temperature and decreased with increase in total solids content and its values varied from 0.278 to 0.491 W/m K. an expression has been proposed for derivation of milk thermal conductivity from temperature and total solids conte

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1988.tb00007.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTExperimental product‐side heat transfer coefficients were studied in a laboratory scale thin‐film wiped‐surface (TFWS) evaporator under different rotational speeds, liquid flow rates and temperatures of the heating medium. Experiments were conducted with water, and 10, 30, and 45% sugar solutions in order to simulate the conditions during evaporation of fruit juices. Dimensionless correlations for heat transfer coefficient were established. It was shown that the “equivalent diameter” of the liquid bow wave formed in the front of wiper blade could be used as a characteristic dimension. Magnitudes of unstable and stable modes of evaporator performance were determined and different regimes related to the liquid flow were

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1988.tb00008.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTThe results of an experimental investigation of the strength characteristics of pressurized food cans are compared with existing models of thin‐walled cylinders as they pertain to the common unbeaded can. After using the data to establish the empirical quantities in the models, good agreement was found between theory and experiment. the models were then used to predict strength characteristics of hypothetical can

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1988.tb00009.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY