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A jacket is a cavity external to the vessel that permits the uniform exchange of heat between the fluid circulating in it and the walls of the vessel. There are several types of jackets, depending on the design: [1] Conventional Jackets. A second shell is installed over a portion of the vessel, creating an annular space within which cooling or ...
The overall heat transfer coefficient is a measure of the overall ability of a series of conductive and convective barriers to transfer heat. It is commonly applied to the calculation of heat transfer in heat exchangers , but can be applied equally well to other problems.
The tanks can be equipped with multiple jackets over its surface, including also the tank bottom, e.g. conical or dished, and can include additional cylindrical shells inside the tank. Typical areas of implementation of pillow plate jacketed tanks are in food and beverage industry and in chemical and pharmaceutical industry.
Q is the exchanged heat duty , U is the heat transfer coefficient (watts per kelvin per square meter), A is the exchange area. Note that estimating the heat transfer coefficient may be quite complicated. This holds both for cocurrent flow, where the streams enter from the same end, and for countercurrent flow, where they enter from different ends.
Formulas and correlations are available in many references to calculate heat transfer coefficients for typical configurations and fluids. For laminar flows, the heat transfer coefficient is usually smaller than in turbulent flows because turbulent flows have strong mixing within the boundary layer on the heat transfer surface. [6]
The number of transfer units (NTU) method is used to calculate the rate of heat transfer in heat exchangers (especially parallel flow, counter current, and cross-flow exchangers) when there is insufficient information to calculate the log mean temperature difference (LMTD). Alternatively, this method is useful for determining the expected heat ...
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Heat balance calorimetry is considered an effective method for measuring heat, as it involves quantifying the heat entering and leaving the system through the heating/cooling jacket using the heat transfer fluid, whose properties are well known. This method effectively measures heat loss or gain, circumventing many calibration issues associated ...