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Phosphorous-Based FRs
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
Nguyen et al. (2014) further investigated the flame retardant performance of the product in Equation 6.22 at different add-ons on cotton fabrics (Nguyen et al., 2013): in particular, the fabrics treated with an add-on beyond 5 wt% showed no after-flame or afterglow time, providing the fabrics with self-extinction. The effect of chemical structure on the performance of these flame retardants was studied using micro combustion calorimeter (MCC). It was found that Total Heat Release (THR) values decreased with increases in the add-on of product of Equation [6.22, R = methyl]. Conversely, THR values were found to increase by increasing the add-on of Equation [6.22, R = ethyl]. The product of Equation [6.23, R = ethyl] promoted char formation and decreased the THR of the treated samples with increases in the add-on on the treated fabrics. However, vertical flammability tests on cotton fabrics treated with the product of Equation [6.23, R = ethyl] showed no afterglow phenomena.
Use of Carbon Nanotubes and Nanofibers for Multifunctional Flame Retardant Polymer Composites
Published in Yuan Hu, Xin Wang, Flame Retardant Polymeric Materials, 2019
In a final example, VGCNF was combined with an organophosphinate (Clariant GmbH OP930) in a bisphenol F, aromatic amine cured epoxy (Morgan and Galaska 2008). Zinc borate was also used in some of the formulations for additional flame retardant enhancement. Via the use of small-scale heat release testing (namely, micro combustion calorimeter, ASTM D7309), the combination of VGCNF, organophosphinate, and zinc borate showed the greatest reduction in heat release when compared to control samples and even samples containing the same flame retardant, but using an organoclay rather than VGCNF as the nanoparticle for flame retardant enhancement.
Annular Microcombustor and Its Characterization
Published in Debi Prasad Mishra, Advances in Combustion Technology, 2023
Swarup Y. Jejurkar, Debi Prasad Mishra
This chapter is devoted to a discussion of the fundamental challenge in micro-combustion, a strategy for heat augmentation devised to address the challenge, and a description of the microcombustor designed to realize this strategy using hydrogen. Discussion is focused on the design of microcombustor, a numerical model to analyze the configuration, and parametric studies using the model.
Flame Propagation and Combustion State Transition in a Sub-millimeter Constant-volume Space
Published in Combustion Science and Technology, 2021
Hang Su, Jiepeng Huo, Xiaohan Wang, Liqiao Jiang, Qianshi Song, Daiqing Zhao
With the advancement of technology, energy system miniaturization is a trend that places higher demands on the capabilities of energy supply systems, such as energy density and battery life. The development of a power system based on combustion is a way to meet these requirements (Dunn-Rankin, Leal, and Walther 2005; Walther and Ahn 2011). Therefore, in the past decade or so, research on micro-energy power systems based on fuel combustion has been very active, and research on related micro-scale scientific issues has attracted extensive attention (Fernandez-Pello 2002; Ju and Maruta 2011; Maruta 2011). As the micro-energy power system is based on fuel combustion, the micro-combustion chamber is the core component of the entire system. However, these micro-scaled systems, which reference conventional power systems, have not achieved the expected performance targets (Dahm et al. 2002; Epstein et al. 1997; Fu et al. 2001), and micro-combustion chambers experience combustion efficiency and instability problems (Zhang, Chou, and Ang 2004). Achieving efficient combustion in micro-combustion chambers is key to improving the output power of micro-energy power systems. The combustion process of the combustion-based micro-energy power system occurs in a millimeter-scale space. Under such extreme conditions, compared with large-scale combustion, micro-scale combustion has the characteristics of high heat loss, short fuel residence times that are limited by the wall material, the chamber structure and wall quenching (Daou and Matalon 2002; Fernandez-Pello 2002).
Role of H2/CO Addition to Flame Instabilities and Their Control in a Stepped Microcombustor
Published in Combustion Science and Technology, 2021
Malhar Malushte, Robin John Varghese, Rahul Raj, Sudarshan Kumar
Ju and Maruta (2011) comprehensively reviewed the various advances and challenges in the field of micro-combustion and suggested that the difficulties in obtaining stable combustion could be overcome through efficient thermal management. Ronney (2003) and (Norton and Vlachos 2003) analyzed the theoretical and numerical aspects related to the importance of the combustor walls and the effect of thermal conductivity on thermal feedback. Maruta et al. (2005) experimentally investigated the dynamics of flame propagation in a straight tube with a positive temperature gradient along the direction of the fluid flow and reported the formation of various stable, oscillating, flame repetitive extinction and ignition (FREI) and weak flames depending on the mixture velocity. Several studies (Frankel and Sivashinsky 1995; Gorman et al. 1996; Kumar et al. 2008; Panfilov, Bayliss, Matkowsky 2003; Pearlman 1997; Pearlman and Ronney 1994; Sivashinsky 1983; Williams 2018; Zik, Olami, Moses 1998) have reported the formation of various flame propagation modes, different patterns and instabilities. They attributed the formation of these flame instabilities to the complex combination of non-linear coupling of fluid mechanics, heat and mass transfer and combustion chemistry. Experimental and theoretical studies on spiral flames (Kumar et al. 2008; Panfilov, Bayliss, Matkowsky 2003; Pearlman 1997; Pearlman and Ronney 1994), cellular flames (Gorman et al. 1996), and fingering instability (Frankel and Sivashinsky 1995; Zik, Olami, Moses 1998) discuss the details of the physical representation of these phenomena. The mixture and flow properties such as hydrodynamics, buoyancy, thermal-diffusive, and viscous fingering (Sivashinsky 1983; Williams 2018) contribute to the formation of these flame instabilities. Pulsating flames, FREI, a combination of pulsations and FREI type of unstable flames formed in these studies were due to the flame bifurcation points and excitation of the oscillations (Maruta et al. 2005).