Fluid physical properties

The fluid physical properties required for heat-exchanger design are density, viscosity, thermal conductivity and temperature-enthalpy correlations (specific and latent heats). Sources of physical property data are given in Chapter 8. The thermal conductivities of commonly used tube materials are given in Table 12.6. 

In the correlations used to predict heat-transfer coefficients, the physical properties are usually evaluated at the mean stream temperature. This is satisfactory when the temperature change is small, but can cause a significant error when the change in temperature is large. In these circumstances, a simple, and safe, procedure is to evaluate the heat-transfer coefficients at the stream inlet and outlet temperatures and use the lowest of the two values. Alternatively, the method suggested by Frank (1978) can be used in which equations 12.1 and 12.3 are combined  

If the variation in the physical properties is too large for these simple methods to be used it will be necessary to divide the temperature-enthalpy profile into sections and evaluate the heat-transfer coefficients and area required for each section. 

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By assuming a reasonable fluid velocity, together with fluid physical properties, standard heat transfer correlations can be used. 

An Excel spreadsheet program (Example 7-l.xls) was developed to determine the theoretical power of any agitator type with given fluid physical properties and tank geometry. 

A software package (MIXER) was developed to determine the heat transfer coefficient for any type of agitator and surface using the value in Table 7-16, fluid physical properties, agitator speed, and diameter. 

Collect together the fluid physical properties required density, viscosity, thermal conductivity. 

Mostinski s equation is convenient to use when data on the fluid physical properties are not available. 

The constants in the heat transfer and pressure drop correlations are functions of the fluid physical properties, volumetric flowrate, tube size and pitch. In preliminary design, it is reasonable to assume either 20 mm outside diameter tubes with a 2 mm wall thickness or 25 mm outside diameter tubes with 2.6 mm wall thickness. The tube pitch is normally taken to be pj = l.25do- A square tube pitch configuration can be assumed as a conservative assumption. Baffle cut can be assumed to be 0.25 in preliminary design. 

Note the similarity between Equations (c) and (a), where x = ht and y = U. From a standard heat transfer coefficient correlation (Gebhart, 1971), you can find that ht also varies according to Ktwt°, where Kt is a coefficient that depends on the fluid physical properties and the exchanger geometry. If we lump 1 /hs and 1 /hf together into one constant l/hsf, the semiempirical model becomes... 

Pure substance, phase behavior of, 24 663 Pure supercritical fluids, physical properties of, 24 4... 

Although the liquid-liquid two-fluid flow has the same phase in the viewpoint of state of matter, some problems might be encountered when utilizing PIV to measure the velocity field(s) in one or both of fluid flows, such as mismatching of refractive indices of the two fluids, physical properties that influence the mixing of seeding particles, resolving the two fluids from each other, etc. 

Fluid Physical Properties at Mean Bulk Temperatures1 3... 

Determined the fluid physical properties required for the model fluid to achieve dynamic similarity between prototype and model. 

Moressi, M. and Spinosi, M. (1984). Engineering factors in the production of concentrated fruit juices, II, fluid physical properties of grapes. ]. Food Technol. 5, 519-533. 

Understanding the rate at which fluids move and mix in the subsurface is crucial for correctly interpreting reservoir geochemical data, and is particularly important for extracting business value from such data. One of the main ways in which reservoir fluid data (here including fluid pressure, fluid physical properties, fluid chemical properties and fluid contacts) are applied is in the detection of reservoir compartmentalization, something that is key for optimizing reservoir development. 

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