CONVECTIVE HEAT EXCHANGE AND AERODYNAMIC RESISTANCE OF STAGGERED BUNDLES OF CIRCULAR TUBES WITH TURNED-UNDER SPIRAL KLM FINS

摘要

Investigations and analyses indicate the energy, technico-economic, operational and ecological expediency of widespread industrial use of bimetallic finned tubes (BFT) with aluminum KLM fins in heat exchanger sections of air coolers (AC), air-cooled condensers of refrigerating and steam-turbine plants, air heaters for air-conditioning systems, and air heaters and heat-recovery units, as well as in other gas-liquid heat exchangers, the temperature of the heating medium of which does not exceed 275℃ at the inlet to the tube. Manufacturers of AC for the oil-refining, chemical, gas, and foodstuff branches of industry, which are currently oriented exclusively toward use of heat-exchange tubes with knurled aluminum fins are the largest consumers of BFT. Analysis of AC use in production processes in the indicated industrial branches has indicated that 70% of AC have a coolant temperature of no more than 275℃. Consequently, the introduction of BFT with KLM fins is possible for these AC. In addition, none of the Russian plants or AC manufacturers produce the new units, or overhaul heat-exchange sections using this structural type of tube finning.