Heat Transfer Performance Research And Development Of Stagger Window Heat Exchanger

Shell and tube heat exchangers are easy to manufacture and can be adapted to a wide temperature and pressure changes in the environment，which is widely used in industrial production. In our country，eighty percent of petrochemical equipment shell and tube heat exchangers are still using segmental baffles smooth tube structure，while this structural shell side pressure drop is high and heat transfer effects are inconspicuous. In order to save energy and improve the economy of industrial production efficiency，it is an important method of energy conservation projects to meet different industrial processes requirements by developing high-performance heat transfer equipment nowadays. Under the guidance of the core heat transfer enhancement，this paper developed a new type of cross-flow tube support structure shell heat exchanger——stagger window baffle heat exchanger，considering both the shell side heat transfer performance and the flow resistance.Stagger window baffle shell and tube heat exchangers include stagger window baffles and tubes. Some open window block interleaving for a period of baffles. Each baffle plate opening area of the window in a different cycle，the window adjacent baffles are staggered，so that the shell side fluid presented portion horizontal and portion vertical continuous flow conditions. This paper proposed two open windows programs of the stagger window baffle heat exchanger——single window baffle heat exchanger and couple window baffle heat exchanger. Single window type：the circular baffle is divided into four quadrants，following by a single quadrant counterclockwise fan-shaped windows，four baffles as a cycle. Couple window type：the circular baffle is divided into four quadrants，staggered fan-shaped windows by first with thirdly quadrants and second with fourthly quadrants，two baffles as a cycle. Through numerical simulation and experimental tests，compared the shell side heat transfer performance of the two open windows programs of the stagger window baffle heat exchanger with segmental baffle heat exchanger.The simulation results showed that the stagger window baffle heat exchanger comprehensive performance were advantageous than the segmental baffle heat exchanger. Single window baffle heat exchanger shell side heat transfer was inconspicuous but the pressure drop was low，therefore the shell side comprehensive heat transfer performance was superior，and the fluid flow in shell presented a counterclockwise spiral pattern. Couple window baffle heat exchanger shell side heat transfer was conspicuous but the flow resistance was relatively larger that result in its shell side comprehensive heat transfer performance were lower than the single window type，which fluid flow in shell main presented a double-spiral pattern. Under the same Reynolds numbers and baffle spacing，the relationships of performance parameters were hoc>hose>hos，ΔPc>ΔPse>ΔPs，(ho/ΔP)s>(ho/ΔP)c>(ho/ΔP)se.The experimental results showed that the stagger window baffle heat exchanger comprehensive heat transfer performance were advantageous than the segmental baffle heat exchanger. Couple window baffle heat exchanger shell side had higher heat transfer efficiency，while single window baffle heat exchanger shell side had lower flow resistance. Under the same baffle spacing （B=300mm）， hoc>hos>hose，while Re<5251，single window shell pressure drop was slightly higher than the other two heat exchanger，the relationship of unit pressure drop heat transfer coefficient was (ho/ΔP)c>(ho/ΔP)s>(ho/ΔP)se，while Re≥5251，the shell side pressure drop relationship was ΔPse>ΔPc>ΔPs，unit pressure drop heat transfer coefficient relationship was (ho/ΔP)s>(ho/ΔP)c>(ho/ΔP)se.