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Heat Release (heat + release)

Distribution by Scientific Domains
Engineering61%
Chemistry22%
Polymers and Materials Science16%

Terms modified by Heat Release

  • heat release rate
    		•

    Selected Abstracts

    Kinetic Regularities of the Heat Release for the Interaction of Some Organic Compounds with Ammonium Nitrate

    PROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 6 2006

    Abstract Ammonium nitrate (AN) is used as an oxidant in a series of systems with a wide spectrum of applications, from explosive compositions up to smokeless stoichiometric self-burning compositions with low combustion temperature. The knowledge of the thermal stability of such compositions is of great importance in using them in practice. In this work the research of kinetics of heat release in the interaction of AN with different organic compounds has been performed using the automatic differential calorimeter. [source]

    Cone calorimeter testing of S2 glass reinforced polymer composites

    FIRE AND MATERIALS, Issue 7 2009
    Alexander B. Morgan
    Abstract With the ever increasing demand for fuel savings on vehicles, there is a strong push to replace metal with polymeric + fiber (carbon/glass) composites. However, the replacement of metal with polymeric composites can lead to additional fire risk. Our study focused on glass fiber reinforced polymer composites meant for vehicular structural applications, and flammability performance of these composites was studied by cone calorimetery. The effects of fiberglass loading, nanocomposite use (clay, carbon nanofiber) and polymer type (epoxy, phenolic) were studied under a heat flux of 50kW/m2 to better understand the potential effects that these variables would have on material flammability. It was found that as fiberglass loading increased, flammability decreased, but at a cost to structural integrity of the residual polymer + fiber char. The use of nanocomposites has little effect on reducing flammability in this set of samples, but the use of phenolic resins in comparison with epoxy resins was found to yield the greatest improvements in flammability performance. Further, the phenolic system yielded a higher level of structural integrity to the final polymer + fiberglass char when compared with the other polymer systems of low heat release. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Cone calorimeter analysis of UL-94 V-rated plastics,

    FIRE AND MATERIALS, Issue 4 2007
    Alexander B. Morgan
    Abstract Cone calorimeter analysis was conducted on 18 thermoplastics with different UL-94 vertical burn test (V) ratings. Ratings varied from V-0 to no rating (NR), and the types of thermoplastics included were polycarbonate (PC), acrylonitrile,butadiene,styrene (ABS), PC/ABS blends, high-impact polystyrene (HIPS), polypropylene (PP), and poly(vinyl chloride) (PVC). Our analysis of the cone calorimeter data found that there were correlations between UL-94 V rating and some cone calorimeter measurements (peak heat release rate (HRR) average and HRR at 60 s) and no relationship for other measurements (time to ignition and total heat release). However, no precise correlation was found due to significant differences in flame retardant mechanism and polymer fuel energy values. In this paper, we seek to explain further why a broad quantitative relationship between UL-94 V and cone calorimeter remains elusive, and also to show how the cone calorimeter can be used to understand why a material passes or fails a particular UL-94 V rating. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Prediction of fire classification for wood based products.

    FIRE AND MATERIALS, Issue 3 2007
    A multivariate statistical approach based on the cone calorimeter
    Abstract Wood has long traditions as a building material, and is often used in construction elements, and as interior and exterior surfaces in the Nordic countries. In most applications, there are reaction to fire requirements to products used as surfaces, e.g. in escape routes and larger public spaces. Most wood products will therefore have to be treated with fire retardant (FR) agents to fulfil the strict requirements to properties connected to heat release and flame spread. Unfortunately, FR agents usually also increase the smoke production, as they cause a more incomplete combustion of the wood. The wood product manufacturers seek to find the optimal amount of FR additives where both heat release and smoke production in the classifying test are within the requirements given in the building regulations. This paper describes models for prediction of the European reaction to fire classes of wood products. The models are based on multivariate statistical analysis, and use test results from the cone calorimeter test as input. The presented models are, with very good precision, able to predict which Euroclass and additional smoke class a wood based product would obtain if it were to be tested in the single burning item test. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Prediction of heat release in the single burning item test

    FIRE AND MATERIALS, Issue 2 2002
    Anne Steen Hansen
    This paper presents a modification of an existing mathematical model that uses cone calorimeter test results to predict heat release rate in the single burning item (SBI) test. A method for classification of cases based on multivariate statistical analysis is incorporated in the modified model. This makes it possible to determine the development of the heat release curve in the SBI test with better precision than the original version was able to. The model has been applied to 100 cases of cone calorimeter test results from 33 different products. For most of the products the predicted shape and level of the heat release curves are close to measurements in the SBI test. Using the predicted heat release results as input to calculation of FIGRA0.2MJ and THR600s within the new European system for reaction-to-fire classification, we were able to predict membership of the correct class in 90% of the analysed cases. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Flame retardant properties of EVA-nanocomposites and improvements by combination of nanofillers with aluminium trihydrate

    FIRE AND MATERIALS, Issue 5 2001
    Günter Beyer
    Flame retardant nanocomposites are synthesized by melt-blending ethylene,vinyl acetate copolymers (EVA) with modified layered silicates (montmorillonites). Thermogravimetric analysis performed under different atmospheres (nitrogen and air) demonstrated a clear increase in the thermal stability of the layered silicate-based nanocomposites. The use of the cone calorimeter to investigate the fire properties of the materials indicated that the nanocomposites caused a large decrease in heat release. The char-formation is the main factor important for improvement and its function is outlined. Further improvements of the flame retardancy by combinations of nanofillers and traditional FR-additives on the basis of metal hydroxides were also studied. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Application of a one-dimensional thermal flame spread model on predicting the rate of heat release in the SBI test

    FIRE AND MATERIALS, Issue 2 2001
    Tuula Hakkarainen
    A one-dimensional thermal flame spread model was applied to predict the rate of heat release in the single burning item (SBI) test on the basis of the cone calorimeter data. The input parameters were selected according to the features of the SBI test and using particle board as a model tuning material. The features of the measured and calculated rate of heat release curves were compared for a series of 33 building products. The fire growth rate (FIGRA) indices were calculated to predict the classification in the forthcoming Euroclass system. The model gave correct classification for 90% of the products studied. An essential feature of the model is that only one cone calorimeter test at the exposure level of 50 kW m,2 is needed. The model, therefore, provides a practical tool for product development and quality control. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Numerical modelling of chemical effects of magma solidification problems in porous rocks

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2005
    Chongbin Zhao
    Abstract The solidification of intruded magma in porous rocks can result in the following two consequences: (1) the heat release due to the solidification of the interface between the rock and intruded magma and (2) the mass release of the volatile fluids in the region where the intruded magma is solidified into the rock. Traditionally, the intruded magma solidification problem is treated as a moving interface (i.e. the solidification interface between the rock and intruded magma) problem to consider these consequences in conventional numerical methods. This paper presents an alternative new approach to simulate thermal and chemical consequences/effects of magma intrusion in geological systems, which are composed of porous rocks. In the proposed new approach and algorithm, the original magma solidification problem with a moving boundary between the rock and intruded magma is transformed into a new problem without the moving boundary but with the proposed mass source and physically equivalent heat source. The major advantage in using the proposed equivalent algorithm is that a fixed mesh of finite elements with a variable integration time-step can be employed to simulate the consequences and effects of the intruded magma solidification using the conventional finite element method. The correctness and usefulness of the proposed equivalent algorithm have been demonstrated by a benchmark magma solidification problem. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Combustion-type hydrogenation of nanostructured Mg-based composites for hydrogen storage

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2009
    M. V. Lototsky
    Abstract In this study Reactive Ball Milling in hydrogen gas was used to synthesize nanostructured hydrogenated composites of Mg and V-based alloy. After hydrogen desorption, the nanocomposites exhibited a dramatic facilitation of the rate of H absorption by Mg and reduction of the temperature of onset of hydrogenation. These favourable changes were caused by a synergy of catalytic effect of the V-based alloy on hydrogen absorption by Mg and heat release caused by exothermic hydrogen absorption by the V-based alloy. When the initial interaction temperature exceeded a threshold, rather low, value of 20,125°C, depending on the H2 pressure, composition of the sample and its total amount, a combustion-type hydrogenation took place. With optimal interaction parameters applied, H absorption was completed in just 5,70,s and was accompanied by a significant heat release. The observed features can be utilized to reach fast recharge of the Mg-based H stores and to develop efficient heat management systems. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Effect of heating rate on kinetics of high-temperature reactions: Mo-Si system

    AICHE JOURNAL, Issue 1 2005
    Suren L. Kharatyan
    Abstract By using the Computer Assisted Electrothermography (CAE) method and taking the molybdenum-silicon system as an example, the influence of preheating rate on the kinetics of gasless reactions at high temperatures (above Si melting point, 1683 K) is studied. It is shown that an increase of heating rate Vh in the range 10,105 K/s, leads to a substantial increase in the rate of chemical reaction. At high heating rates (>103 K/s), the first stage of interaction involves rapid reaction due to the direct dissolution of Mo in the Si melt. Furthermore, the formation of MoSi2 phase, owing both to crystallization from eutectic (MoSi2 -Si) melt and reaction-diffusion mechanism, is primarily responsible for the observed intensive heat release under these conditions. At lower Vh, a thin layer of Mo5Si3 phase formed at earlier stages (solid-solid interaction) significantly retards reaction at higher temperatures and changes the mechanism of interaction. Some methodological aspects of using the CAE technique for kinetic studies are also discussed. © 2004 American Institute of Chemical Engineers AIChE J, 51: 261,270, 2005 [source]

    Fire and flame retardants for PVC

    JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2003
    A. William Coaker
    The flammability performance of PVC plays a significant role in its selection for many applications. Its relatively high chlorine content (56.8%) makes it more resistant to ignition and burning than most organic polymers. In the case of flexible PVC, the plasticizers that contribute flexibility in most instances detract from its resistance to fire. To meet specifications such as oxygen index, heat release, smoke evolution, or extent of burning in cable tests, flame-retardant (FR) and smoke-suppressant (SS) additives are often incorporated. Synergistic combinations of FR and SS additives help PVC formulations meet many stringent FR specifications cost effectively. [source]

    Flame resistance and foaming properties of NBR compounds with halogen-free flame retardants

    POLYMER COMPOSITES, Issue 12 2009
    SungCheal Moon
    Acrylonitrile butadiene rubber (NBR) foams compounded with various halogen-free flame retardants were prepared. The influence of nonhalogen flame retardants on the flame resistance and foaming properties of the NBR compounds were investigated. The foaming properties (expandability 980%,1050%, closed-cell structure) of NBR compounds with expandable graphite (EG) and ammonium polyphosphate (APP) flame retardants were similar to the NBR base compounds which contained primarily aluminum hydroxide (ATH). The heat release capacity (HRC) ranged from 10 to 74 J/g-K, the average heat release rate (A-HRR) ranged from 8 to 60 kW/m2, and the total heat release (THR) ranged from 2.6 to 7.3 MJ/m2 for the nonhalogenated NBR foams with closed-cell structure and were significantly decreased upon increasing the amounts of flame retardants. This reduction is attributed to the hard char formation and production of water from the interaction with ATH. The limiting oxygen index (LOI) and time to ignition (TTI) show opposite results. The smoke density (0.050,0.037) of the NBR foams with EG flame retardant was decreased when compared to the NBR foam (0.107). The EG flame retardant was more effective than the phosphorus/nitrogen flame retardants in reducing the HRR and smoke density. The use of both ATH and EG is very effective in improving flame resistance. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers [source]

    Effects of poly(ethylene- co -propylene) elastomer on mechanical properties and combustion behaviour of flame retarded polyethylene/magnesium hydroxide composites

    POLYMER INTERNATIONAL, Issue 7 2002
    Zhengzhou Wang
    Abstract Magnesium hydroxide-based halogen-free flame retarded linear low density polyethylene composites containing poly(ethylene- co -propylene) elastomer were prepared in the melt process and subsequently vulcanized thermally. Influences of the elastomer on the mechanical properties, combustion characteristics and crystallization behaviour of polyethylene/magnesium hydroxide composites have been investigated. The results from the mechanical tests show that the incorporation of a suitable amount of elastomer into polyethylene/magnesium hydroxide composites after vulcanization can increase both the tensile strength and elongation greatly, compared with those of the composites without the elastomer. It has been found that the properties such as limiting oxygen index, UL-94 rating, the time to ignition and the rate of heat release of polyethylene/magnesium hydroxide/elastomer composites are all improved in comparison with polyethylene/magnesium hydroxide composites at the same retardant level. Scanning electron microscopy studies show that the incorporation of the elastomer into polyethylene/magnesium hydroxide composites improves the compatibility between the filler and the polymer substrate. The degrees of crystallinity of polyethylene/magnesium hydroxide/elastomer composites decrease with increasing the elastomer content. © 2002 Society of Chemical Industry [source]

    Kinetic Regularities of the Heat Release for the Interaction of Some Organic Compounds with Ammonium Nitrate

    PROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 6 2006

    Abstract Ammonium nitrate (AN) is used as an oxidant in a series of systems with a wide spectrum of applications, from explosive compositions up to smokeless stoichiometric self-burning compositions with low combustion temperature. The knowledge of the thermal stability of such compositions is of great importance in using them in practice. In this work the research of kinetics of heat release in the interaction of AN with different organic compounds has been performed using the automatic differential calorimeter. [source]

    Novel Process Windows , Gate to Maximizing Process Intensification via Flow Chemistry

    CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2009
    V. Hessel
    Abstract Driven by the economics of scale, the size of reaction vessels as the major processing apparatus of the chemical industry has became bigger and bigger [1, 2]. Consequently, the efforts for ensuring mixing and heat transfer have also increased, as these are scale dependent. This has brought vessel operation to (partly severe) technical limits, especially when controlling harsh conditions, e.g., due to large heat releases. Accordingly, processing at a very large scale has resulted in taming of the chemistry involved in order to slow it down to a technically controllable level. Therefore, reaction paths that already turned out too aggressive at the laboratory scale are automatically excluded for later scale-up, which constitutes a common everyday confinement in exploiting chemical transformations. Organic chemists are barely conscious that even the small-scale laboratory protocols in their textbooks contain many slow, disciplined chemical reactions. Operations such as adding a reactant drop by drop in a large diluted solvent volume have become second nature, but are not intrinsic to the good engineering of chemical reactions. These are intrinsic to the chemical apparatus used in the past. In contrast, today's process intensification [3,12] and the new flow-chemistry reactors on the micro- and milli-scale [13,39] allow such limitations to be overcome, and thus, enable a complete, ab-initio type rethinking of the processes themselves. In this way, space-time yields and the productivity of the reactor can be increased by orders of magnitude and other dramatic performance step changes can be achieved. A hand-in-hand design of the reactors and process re-thinking is required to enable chemistry rather than subduing chemistry around the reactor [40]. This often leads to making use of process conditions far from conventional practice, under harsh environments, a procedure named here as Novel Process Windows. [source]