Heat and mass transfer in hot-particle-induced ignition of a liquid-fuel vapor entering the ambient air from the surface of fabric impregnated with the fuel

2009 ◽  
Vol 82 (3) ◽  
pp. 448-455 ◽  
Author(s):  
G. V. Kuznetsov ◽  
P. A. Strizhak
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Liquid Fuel ◽  
Ambient Air ◽  
Fuel Vapor ◽  
Hot Particle ◽  
Induced Ignition

Numerical Study of Heat and Mass Transfer at the Ignition of Condensed Substances by Hot Particles

2016 ◽  
Vol 683 ◽  
pp. 555-562
Author(s):  
Dmitrii O. Glushkov ◽  
Pavel A. Strizhak ◽  
Ksenia Yu. Vershinina
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Liquid Fuel ◽  
Ignition Delay Time ◽  
Numerical Study ◽  
Local Energy ◽  
Composite Propellant ◽  
Hot Particle ◽  
Solid Liquid ◽  
Ignition Zone

Mathematical models of ignition of condensed substances considering interconnected processes of a heat and mass transfer in systems “composite propellant – hot particle – gas”, “liquid fuel – hot particle – air” and “gel-like fuel – hot particle – gas” were developed. As a result of numerical modeling modes of ignition for solid, liquid and gel-like condensed substances characterized by ignition delay time and arrangement of ignition zone relative to local energy source were established. Liquid fuel has 3 ignition modes, composite propellant and gel-like fuels have 1 ignition mode

Naturally Driven Flow, Heat and Mass Transfer in Soil Saturated With Light Fuel Vapor and Heated Asymmetrically

2001 ◽  
Author(s):  
A. A. Mohamad ◽  
G. A. Karim
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Heat And Mass Transfer ◽  
Ambient Air ◽  
Fuel Vapor ◽  
Complex Flow ◽  
Flow Temperature ◽  
Fire Hazards ◽  
Thermally Driven ◽  
Flow Heat

Abstract Natural convection heat and mass transfer in a soil saturated with light fuel vapor and heated from one side is modeled and solved numerically. The system is simulated as a porous medium in a large horizontal enclosure exposed to ambient air from the top and saturated with a fuel vapor from the bottom. It is assumed that one of the vertical boundaries is heated to a constant temperature while the other vertical boundary kept cold at the ambient temperature. The problem is approximated as a two-dimensional, steady state, laminar flow with constant properties. The rate of outflow of species is calculated together with the rates of heat and mass transfer. Also, flow, temperature and species distributions are shown. For a thermally driven flow, i.e., N<1.0, the flow is driven into the cavity from a distance if the strength of the heat source and/or the permeability of the porous medium is high. For N>1.0, solutal plumes and complex flow pattern are formed as N increases. Such results will aid in providing guidelines for reducing the fire hazards from fuel wetted soils.

Heat and Mass Transfer Analysis of a Pot-in-Pot Refrigerator Using Reynolds Flow Model

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Ramendra Pandey ◽  
Bala Pesala
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Ambient Temperature ◽  
Heat And Mass Transfer ◽  
Heat Load ◽  
Radiation Heat Transfer ◽  
Ambient Air ◽  
Total Heat ◽  
Maximum Efficiency ◽  
Radiation Heat

Heat and mass transfer analysis of evaporative cooling process in a pot-in-pot cooling system is done based on Reynolds flow hypotheses. The model proposed herein assumes that the heat transfer due to natural convection is coupled with an imaginary ambient air mass flow rate (gAo) which is an essential assumption in order to arrive at the solution for the rate of water evaporation. Effect of several parameters on the pot-in-pot system performance has been studied. The equations are iteratively solved and detailed results are presented to evaluate the cooling performance with respect to various parameters: ambient temperature, relative humidity (RH), pot height, pot radius, total heat load, thermal and hydraulic conductivity, and radiation heat transfer. It was found that pot height, pot radius, total heat load, and radiation heat transfer play a critical role in the performance of the system. The model predicts that at an ambient temperature of 50 °C and RH of 40%, the system achieves a maximum efficiency of 73.44% resulting in a temperature difference of nearly 20 °C. Similarly, for a temperature of 30 °C and RH of 80%, the system efficiency was minimum at 14.79%, thereby verifying the usual concept that the pot-in-pot system is best suited for hot and dry ambient conditions.

Geometrical Effects of Cabinet Size and Aspect Ratio on Heat and Mass Transfer During Open Door Conditions

2005 ◽  
Author(s):  
W. Terrell
Keyword(s):  
Mass Transfer ◽  
Aspect Ratio ◽  
Heat And Mass Transfer ◽  
Ambient Air ◽  
Open Door ◽  
Nusselt Numbers ◽  
Aspect Ratios ◽  
Mass Fluxes ◽  
Geometrical Effects ◽  
Aluminum Plates

The goal of this paper is to examine the effects of size and aspect ratio (H/L) of open cavities on heat and mass transfer during open door conditions of refrigerator cabinets. An experimental investigation was conducted using test cavities constructed from foam board insulation and interior covered with aluminum plates acting as calorimeters. Various size cavities with heights of 15.24 cm, 30.48 cm, and 45.72 cm along with aspect ratios of 0.5, 1.0, and 2.0 were tested. Cavities were heated to an initial temperature of 50°C, 60°C, 70°C, and 80°C before being exposed to the ambient air. In addition, tests were conducted in which the cavities were cooled before being exposed to the ambient. The relative humidity was varied from 60% to 75% and initial temperatures varied from 5°C, 1°C, and −5°C. The cavity mass fluxes were measured to validate the heat/mass transfer analogy for the tests. Experimental results were also presented for Rayleigh numbers from 5.88 × 106 to 2.21 × 108 with Nusselt numbers ranging from 15.48 to 53.51. The Nusselt numbers for cavities with an aspect ratio of one and two were in good agreement with each other. The Nusselt numbers for the cavity with an aspect ratio of 0.5 were slightly lower than the other cavities at given Rayleigh values.

Mathematical Modeling of a Thin Layer Solar Kiln

1990 ◽  
Vol 112 (3) ◽  
pp. 196-203 ◽  
Author(s):  
Moustafa M. Elsayed
Keyword(s):  
Mathematical Modeling ◽  
Mass Transfer ◽  
Thin Layer ◽  
Heat And Mass Transfer ◽  
Initial Conditions ◽  
Ambient Air ◽  
Glass Temperature ◽  
Humidity Ratio ◽  
Solar Kiln ◽  
Empirical Relations

Mathematical modeling of a thin layer solar kiln for drying of agricultural products is presented. Governing equations of the air temperature and air humidity ratio, material temperature and its moisture content, and the glass temperature are derived together with their initial conditions. Heat and mass transfer between the material and the air and the air and the glass cover are estimated using empirical relations for the coefficients of heat and mass transfer. The results of the calculations are analyzed to predict the effect of the following parameters on the transient performance of the kiln: (a) rate of absorbed solar energy in the kiln, (b) rate of air flow through the kiln, (c) volume of the dried material, (d) ambient temperature, and (e) humidity ratio of the ambient air.

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