摘要:

ABSTRACTOrifice discharge coefficients for non‐Newtonian (power‐law) fluids (5, 7.5 and 10% corn starch solutions) were measured using a closed end pipe with different orifice diameters. Results indicate that orifice discharge coefficients, found to be in the range of 0 – 0.7, are a function of the orifice diameter, fluid velocity in the orifice and the fluid rheological properties (consistency coefficient and flow behavior index). They increase with the fluid velocity, tend to be constant at high velocities and decrease when the consistency coefficient of the solution is increasing. Orifice discharge coefficients are presented as a function of the generalized Reynolds n

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00043.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTThe compaction behavior of two dehydrated potato granule materials has been studied in a cylindrical geometry. the effect of moisture content and the addition of dehydrated potato flake and potato starches has also been considered. the coefficient of friction and the stress anisotropy factor have been calculated from the pressure transmission measurements using a semi‐particulate analysis previously used for polymer powders. the two granule types behaved more similarly under those conditions than their Brabender consistencies implied. the stress anisotropy factor tended to unity with increasing moisture content. the presence of other potato materials had a considerable effect on the compaction of the granules. These results indicate that the performance of processes that involve compaction of these materials, such as extrusion, will vary considerably with composition and moisture conten

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00044.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTA set of analytical equations for a triple‐tube heat exchanger was developed. They allow for independent computations of bulk (cross‐sectional area averaged) fluid temperatures at any axial location along the heat exchanger and are valid for parallel and counter flow configurations. the equations account for heat losses to the surroundings and are useful for design purposes. Mass flow rates, inlet fluid temperatures and heat transfer coefficients are input parameters required for temperature calculations. A simplified approximate equation for total rate of heat transfer, in terms of logarithmic mean temperature differences, was derived for well‐insulated heat exchangers and tested with the analytical equations. A case study is presented and the computational procedure is discussed. Results obtained with the simplified total rate of heat transfer equation were in excellent agreement with those obtained with the analytical equations. Simulations show that the creation of an annular region within the inner pipe increases the overall heat transfer efficiency and reduces the heat exchanger length requirement by almos

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00045.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTWith the objective of producing high quality and economical starting material for restructured beef products, the use of a high pressure water jet was investigated for excising objectionable material from slices of bone‐in beef chuck. From the limited number of tests conducted, best conditions for a clean, smooth cut were obtained with a water jet orifice diameter of 0.15 mm (0.006 in), a water pressure of 380 MPa (55,000 PSI), a slice thickness of 19 mm (3/4 in) and a linear cutting speed of 10.9 m/min (430 in/min). A preliminary cost comparison indicated that a fully automated line had a greate economic advantage over the manual metho

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00046.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTDrag forces on rigid spherical particles suspended at specific points in a tube carrying viscous solutions of sodium carboxymethylcellulose (CMC) were measured using a load cell. Polystyrene spheres of diameter 1, 2.22 and 3.175 cm were used in a plexiglass tube of 4.75 cm internal diameter. the range of consistency coefficient of the carrier fluid studied was 5 to 16 Pa‐sn. Mass flow rate was varied between 0.01 and 0.9 kg/s. the drag coefficient‐generalized particle Reynolds number correlation developed from linear regression was: Cd = 101.35/[(NRe)p]0.84/n. This correlation may be used to estimate drag forces on suspended spherical food solids in aseptic holding tu

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00047.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY