Combustion and fire safety of energy conservation materials in building vertical channel: Effects of structure factor and coverage rate

Effects of methane addition on laminar flame characteristics of premixed blast furnace gas/air mixtures

Experimental study on the flame length and burning behaviors of pool fires with different ullage heights

With the potential safety hazard of coal spontaneous combustion becomes more and more serious, in order to solve the problems of low water absorption rate and high cost of hydrogel inhibitor, in this study, a superabsorbent lignin-based composite inhibitor (SAP + SLS + Ben) was prepared. The water absorption/retention rate, micromorphology, inhibition capacity, air-leakage blocking efficiency and fire-extinguishing performance of SAP + SLS + Ben were studied. Results have revealed that: SAP + SLS + Ben had excellent water absorption/retention capacity; SEM images revealed that sodium lignosulfonate (SLS) and bentonite (Ben) provided the structural basis for the high water absorption/retention of SAP + SLS + Ben; Compared with SAP, SAP + SLS + Ben could effectively inhibit the oxidation of reactive functional groups in coal, and the amount of CO released from coal treated with SAP + SLS + Ben was significantly reduced at high temperature; The air-leakage blocking and fire-extinguishing experiments showed that SAP + SLS + Ben had good filling and blocking performance, and could effectively reduce the temperature of coal spontaneous combustion and prevent the re-ignition of coal. Hence, SAP + SLS + Ben had ideal physical and chemical inhibition properties, which could effectively prevent coal spontaneous combustion in goaf. 

Preparation of superabsorbent lignin-based composite inhibitor and research on its prevention and control characteristics of coal spontaneous combustion

An experimental study on upward flame spread over corrugated cardboard used in underground logistic transportation: Influence of grain orientation and thickness

Influence of U-shaped structure on upward flame spread and heat transfer behaviors of PMMA used in building thermal engineering

Considering disadvantages such as the low thermal stability and environmental pollution of existing gel inhibitors, a green and stable intumescent nanoinhibitor (INI) was prepared and tested. First, polyacrylamide (PAM), nano-silica, and intumescent flame retardant (IFR) were selected as raw materials. The INI was prepared by nanoparticle modification and cross-linking polymerization. Then, the structure and physical properties of INI were tested by Fourier transform infrared spectroscopy, scanning electron microscopy, and rheological experiments. Meanwhile, the inhibition performance of INI was studied through thermogravimetric analysis-Fourier transfer infrared spectroscopy (TGA-FTIR) analysis. The results suggest that the nanomodification improved the dispersibility of INI particles. The addition of modified nano-silica (MNS) and IFR enhances the strength of the reticular structure, thereby improving the transport convenience and covering ability of the INI gel. At high temperatures, IFR can generate a porous foamed carbon layer that further coats the coal. After INI inhibition treatment, the characteristic temperature and activation energy of coal were significantly improved, and the production of carbon monoxide and carbon dioxide decreased. Hence, irrespective of physical properties, physical inhibition performance, or chemical inhibition performance, INI performed well. Research results can provide valuable references for the preparation and performance study of a coal spontaneous combustion inhibitor.

https://pubs.acs.org/doi/pdf/10.1021/acsomega.2c00998

Characterization and Performance Testing of an Intumescent Nanoinhibitor for Inhibiting Coal Spontaneous Combustion

Simultaneous thermal analysis and Fourier transform infrared spectroscopy in situ diffuse reflection technology were used to quantitatively study the quality and functional groups of lignite during the oxidation process according to temperature. The Kubelka-Munk equation and the Starink method were used to calculate the oxidation kinetics of functional groups for the first time. The results show that the oxidation and heating process of lignite varies in stages, including a water evaporation and desorption stage, an oxygen absorption and weight gain stage and a thermal decomposition stage. The main functional groups in coal include -OH, C = O, CH2/CH3, C = C and CH-, which exhibit different oxidation characteristics in each stage. This study provides a method for calculating the oxidation kinetics of functional groups, which overcomes the indirectness of the conversion of reference mass and can be used to reveal the different oxidation processes of various functional groups in the coal oxidation process. 

A kinetic research method for coal oxidation based on the Kubelka-Munk equation and the Starink method

A novel nano-modified inhibitor of tert-butyl hydroquinone/sodium polyacrylate for inhibiting coal spontaneous combustion

The application of variable helical end mills to the milling of titanium alloys can suppress the regeneration effect during the machining process and ensure the stability of milling. However, due to their special geometry, their milling characteristics are also different. In this paper, the process of milling titanium alloy with a variable helix end mill is taken as the research object, and the milling force, milling stability and machining effect during the machining process are deeply studied. Firstly, the feed per tooth and cutting thickness model of the variable helical end mill were established, the milling force prediction model of the variable helical end mill was deduced, and the instantaneous milling force and its variation law were obtained by solution. Secondly, the finite element analysis model of the variable helix end mill for machining titanium alloy was established, and the influence of the variable helix angle structure on the milling force was obtained. Then, the dynamic equation of milling with a variable helix end mill was established, the stability lobe diagram of variable helix milling is was and drawn, and the influence of variable helix angle on milling stability was analyzed. Lastly, a variable helix end mill milling experiment was designed to verify the accuracy of the theoretical model and finite element simulation; the influence of the variable helix angle structure on the surface roughness was analyzed, and the influence of machining parameters on the milling force when using a variable helix end mill was investigated.

/pdf/research-on-milling-characteristics-of-titanium-alloy-tc4-151xfog5.pdf

Xiangming Hu

Papers

Influence of U-shaped structure on upward flame spread and heat transfer behaviors of PMMA used in building thermal engineering

Characterization and Performance Testing of an Intumescent Nanoinhibitor for Inhibiting Coal Spontaneous Combustion

A kinetic research method for coal oxidation based on the Kubelka-Munk equation and the Starink method

A novel nano-modified inhibitor of tert-butyl hydroquinone/sodium polyacrylate for inhibiting coal spontaneous combustion

Research on Milling Characteristics of Titanium Alloy TC4 with Variable Helical End Milling Cutter