Improving heat exchanger efficiency using the pulsed method of cleaning

Abstract

The fouling of heat exchange equipment leads to serious economic losses in many industries, therefore to find a method to reduce deposits on heat transfer surfaces remains an actual task. In this paper, a practical solution is proposed for the implementation of a pulsating cleaning method of oil coolers as an example. The influence of pulsations on cleaning of the external surface of the heat exchanger is studied by computer modeling with Ansys Fluent. The fluid flow was described by the Navier-Stokes equation, particle motion and their interaction was described by the discrete element method (DEM). In the study, a staggered tube bundle was considered. The pulse frequency 0,3125 Hz, the amplitude referred to the diameter of tube is 35, the Reynolds number 100, the duty cycle of the pulsations 0,25. Oil was chosen as the medium. Evaluation of the pulsating cleaning method was carried out on the basis of the analysis of the mechanics of particle collisions on the surface of the central cylinder in the beam, with stationary and pulsating flow. It was found that the pulsating flow helps to reduce deposits in the front of the cylinder and is not effective in the back. An analysis of the mechanics of particle impact on the heat exchange surface showed that this pulsation mode is more effective for removing plastic deposits.

Increasing the efficiency of heating systems through the use of direct contact heat exchange

“…As methods for increasing the efficiency of heating installations from the inside, one can note a reduction in scale formation in the heating systems of heat exchangers of heating installations [4]; increasing the efficiency of heat exchangers through the use of profile twisted tubes [5]; development of methods for improving the fins of heat exchangers [6]; use of pulsation cleaning methods [7]; the use of a built-in surface cooler in the heat exchange process [8]; increasing the efficiency of heat transfer through the use of a round cylinder in laminar pulsating transverse flows [9][10][11].…”

“…The technical essence of this method is illustrated by a drawing, which shows a diagram of the basic design of a heating installation for implementing the proposed method of heating the coolant liquid. The heating installation contains a housing (1) in which a heat source (2) is located, into which fuel (3) and air (4), cold liquid coolant ( 5) is supplied, which is supplied from a pump (not shown in the drawing) through a pipeline ( 6) supplying liquid coolant tangentially to the inner surface of the housing (7) into the cavity (8) formed by the inner surface of the housing (7), the outer surface of the guide wall (9) and the end partition (10) connecting these surfaces; removal of heated coolant liquid (11) for consumption.…”

“…The heating installation operates as follows: fuel (3) and air (4) are supplied to the heat source 2 located inside the housing (1), forming a combustion process on the outer surface of the heat source (2), and cold liquid coolant ( 5) is supplied to the heating zone. through the pipeline (6) tangentially to the inner surface of the housing (7) into the cavity (8) formed by the inner surface of the housing (7), the outer surface of the guide wall (9) and the end partition (10) connecting these surfaces. In this case, a near-wall layer of liquid coolant is formed on the inner surface of the housing, which moves simultaneously coaxially and tangentially, rotating towards the base of the housing (1) and the heated liquid coolant (11) is selected for consumption.…”