Abstrakt

A dynamic development of technologies allowing waste heat utilization is observed in a correspondence with a pro-ecological approach of the zero waste idea. Such approach becomes the most demanding in the area of low-temperature was heat sources, especially gaseous media. Till now, they were usually not utilized due to unfavorable thermal conditions and high costs. Therefore, the zero waste approach directs research on techniques for heat exchange intensification and increasing heat transfer coefficients. In many cases, it is connected with the compact heat exchangers oriented on the low-temperature heat recovery from gaseous sources. Passive intensification methods, characterized by low energy consumption are primarily desirable. The shell-and-tube heat exchanger is a type of commonly applied unit in various industry branches, that is why it is considered as the most suitable for improvements. The passive techniques, implemented in it, are very often connected with various types of inserts in the bundle of tubes, which intensify the heat exchange process on the gas side and are a relatively simple modification even of existing heat exchangers. The inserts are of various shapes, optimized toward particular applications and sometimes combined with other techniques. Following the pro-ecological approach, the authors proposed an innovative shell-and-tube heat exchanger a new type of inserts, designed to transfer high heat fluxes. Proposed construction based on the previous experiences with the impinging jets technology, which confirmed its validity in the cylindrical heat exchangers. Novelty of the tube inserts relies on generation of jets impinging on the heat exchange surface. To enhance a compactness of the heat exchanger, the minichannels technology was also implemented - the inlet diameter of single perforated tube is 2 mm. In this paper the construction and principles of operation of described shell-and-tube heat exchanger were discussed. The experimental stand and investigations of heat exchanger thermal performance in a single-phase convection in the gas-liquid system were presented. Analysis of obtained data provides the basis for further development of a correlation describing the Nusselt number for shell-and-tube heat exchangers with impinging jet technique.

Autorzy (4)