Industrial thermal engineering

The latest publications in this offer are:

• December 18, 2024

  BE9517 Review

  Heat exchangers

  In this article, the principles of the sizing of a heat exchanger together with that of rating an existing heat exchanger are given. Two approaches are described, an analytical one and a numerical approach. In the analytical approach, the two main methods are proposed: the so-called LMTD (Logarithmic Mean Temperature Difference) method more adapted to sizing and, the effectiveness – NTU (Number of Transfer Units) method more adapted to rating. For numerical approach, after some bases about numerical methods, the emphasis is put on examples of utilization showing the given help to the analysis of sizing and possible conception mistakes (distribution, internal geometries, heat transfer intensification…)

• August 30, 2023

  BE8731 Review

  Boilers. Combustion systems, water/steam and air/flue gas circuits

  This article provides an overview of the component systems of a boiler with the design criteria of exchangers (pressure parts and others) and air/smoke circuits. It mainly details combustion systems and their specificities as well as the types of water/steam circulation (natural, pump-assited, forced, etc.). It also presents the case of exchangers in pressure parts and provides advice regarding the choice of materials. It ends on the analysis of air/smoke circuits (nature of the circuits, air-heaters, ventilators, etc).

• March 10, 2022

  BE9850

  Insulation

  Technical insulation consists, by definition, of insulating equipment in industrial installations or buildings, in order to avoid heat loss. This makes it possible, among other things, to protect these installations against external disturbances such as frost, condensation, but also to conserve thermal energy and therefore limit greenhouse gas emissions. After the description of thermal principles and physical phenomena, this article details the methods for efficiently carrying out thermal insulation of equipment. The different insulating materials and examples of calculations are also presented.

• February 18, 2022

  BE9520 Review

  Heat exchangers

  The unsteady operation of exchangers, whatever they may be, is a daily reality met on thermal systems using such equipment. The challenge is a better knowledge of transient behaviors for an adapted control-command.Several approaches appear centered essentially on the physical mechanisms, or on the opposite, on a systemic vision. It comes out the fundamental concept of time constant, supplemented by the notion of delay time (or even phase shift). The utility of the previous set is shown on examples.

• September 28, 2021

  BE9570 Review

  Heat and cold transfer fluids

  The role of a heat transfer fluid is to transport heat from a heat source to a heat sink, while maintaining all constraints: technical (reduced heat losses, low fluid transport energy consumption), safety and reduced environmental impact, economic constraints (related to the size of the auxiliary pumping, compression or ventilation but also the size of the heat exchanger providing heat transfer between the coolant and the source and the heat sink). Their selection for a thermal process is the result of a complex process of evaluating various parameters and criteria.

• September 28, 2021

  BE9571 Review

  Heat transfer fluids

  The main heat transfer fluids are gases such as nitrogen, helium, air, carbon dioxide and superheated steam. They are characterized by a poor heat carrying and cooling power, but are adaptable to very high temperature. For industrial processes operating at temperatures up to 350 °C, fluids such as mineral or synthetic oil may find wide applications. Halogenated fluids of the PFC or HFE type find uses where dielectric strength and low volatility are applied to cooling in various processes Uses at higher temperature demand heat transfer fluids such as molten salts or liquid metals, whose implementation remains difficult despite their particularly favorable physical properties.

• June 25, 2021

  BE9515 Review

  Heat exchangers

  The heat exchanger, key instrument for thermal or energy engineers, is a device which allows the temperature of a system or a substance to be controlled when exchanging heat from a medium to another. It is essential in many usual applications: heating, air-conditioning, refrigeration, electronic cooling, in process industries, in energy storage or for mechanical (or electrical) energy production in power plants. In a classical heat exchanger, a hot fluid exchanges a part of its enthalpy to a cold fluid. This type of heat exchanger will serve as a reference in this article to give definitions and parameters required for understanding phenomena and for sizing or rating. Other types of existing heat exchangers will also be mentioned.

• June 14, 2021

  BE9516 Review

  Heat exchangers

  Main industrial technologies to manufacture heat exchanger are described. Various criteria of classification are presented: by technology, by process or heat transfer mode, by application, by wall material. A table gives the main types of heat exchangers according to these criteria. The most used kinds of heat exchangers are detailed (Shell and tube, Plate, etc.) by specifying the applications for which they are the best suited.

• April 26, 2021

  BE9518 Review

  Heat exchangers

  Heat Transfer Enhancement has overcome the laboratory field for several years, and is widely spread in industrial applications. Many heat exchangers in various processes are now equipped with plates or tubes especially designed to increase the heat transfer coefficients, which exhibit high operational values well above those obtained with flat surfaces.

• April 26, 2021

  BE9519 Review

  Heat exchangers

  Heat exchanger main operating problems are due to fouling, corrosion, vibration and mechanical strength phenomena. Corrosion and fouling remain the most misunderstood phenomena in the industrial field. They impact sizing and aging of the equipment, and induce overheads (energy, shutdowns). Vibration resistance must be taken into account in heat exchanger design together with heat transfer and pressure loss. Mechanical strength problems are, for most common geometries, solved by applying various regulatory texts based on European standardization. Finally, transient state in heat exchanger can deal with new kind of operation (unsteady heat sources) or check their ability to bear variable operating conditions.

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