Concurrent heat transfer method for magnetic field reinforced shell-and-tube heat exchanger

Abstract

The invention belongs to the technical field of heat exchanger enhanced heat transfer, discloses a magnetic field enhanced convective heat transfer method for a shell-and-tube heat exchanger, and provides a method for using magnetic nanofluid as a working medium in the shell-and-tube heat exchanger and applying a magnetic field to the outside in order to improve the flow heat transfer performance of the shell-and-tube heat exchanger. And the convective heat exchange performance of the shell-and-tube heat exchanger is enhanced due to the influence of the magnetic field on the magnetic nanofluid. Compared with a heat exchanger without adding magnetic nanoparticles and applying a magnetic field, the heat transfer rate is greatly improved and the comprehensive heat transfer performance is remarkably enhanced under the condition of little influence on pump power consumption, and compared with other shell-and-tube heat exchanger enhanced heat transfer methods, the method has certain advantages and is easy to implement, energy input equipment does not need to be additionally arranged, and the cost is reduced. The magnetofluid working medium is used in the shell-and-tube heat exchanger, and the permanent magnet is placed outside the shell-and-tube heat exchanger; on the basis of not changing the original structural design of the heat exchanger, the heat transfer rate can be greatly improved, the comprehensive heat transfer performance of the heat exchanger is improved, and popularization value is achieved.

Description

technical field [0001] The invention belongs to the technical field of heat transfer enhancement of heat exchangers, and in particular relates to a method for enhancing convection heat transfer of a shell-and-tube heat exchanger by a magnetic field. Background technique [0002] At present, the existing technologies for heat transfer enhancement of heat exchangers are divided into two categories: active enhancement and passive enhancement. Active strengthening is a strengthening method that requires input of external work, mainly including surface vibration, electric field, jet impact, etc.; passive strengthening starts from the structure and working fluid of the heat exchanger, such as using special-shaped tubes, arranging turbulent structures, using rough surfaces, Improve working fluid performance, etc. At present, passive strengthening technology is generally used. The complex structure proposed by passive strengthening technology often has higher requirements on the ma...

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Problems solved by technology

[0004] The complex structure proposed by the passive strengthening technology often has higher requirements on the manufacturing process of the heat exchanger, and there are uncertainties in the stability and durability of the use process

[0005] The existing active strengthening methods of heat exchangers are often difficult to use in industrial processes due to complex equipment, high investment costs, vibration and noise

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