图书馆订阅: Guest
Begell Digital Portal Begell 数字图书馆 电子图书 期刊 参考文献及会议录 研究收集
国际计算热科学期刊
ESCI SJR: 0.249 SNIP: 0.434 CiteScore™: 0.7

ISSN 打印: 1940-2503
ISSN 在线: 1940-2554

国际计算热科学期刊

DOI: 10.1615/ComputThermalScien.2013006896
pages 425-440

NUMERICAL STUDY OF RADIATION AND AIRPREHEATING EFFECT ON THE VELOCITY, TEMPERATURE, AND SPECIES DISTRIBUTION IN A CONFINED LAMINAR COFLOW DIFFUSION FLAME

A. K. Chowdhuri
Department of Mechanical Engineering, Bengal Engineering and Science University, Shibpur, Howrah 7111103, India
Somnath Chakrabarti
Department of Mechanical Engineering, Indian Institute of Engineering Science and Technology Shibpur, Howrah, 711103, West Bengal, India
Bijan Kumar Mandal
Department of Mechanical Engineering, Bengal Engineering and Science University, Shibpur, Howrah 7111103, India

ABSTRACT

The effect of gas-band and soot radiation has been numerically investigated in a coflow laminar confined methane-air buoyant jet diffusion flame using non-preheated and preheated air. A specially developed computer code based on the SOLA algorithm is used to solve the overall mass, species mass concentration, momentum (Navier Stokes), and energy conservation equations along with appropriate boundary conditions. A two-equation semiempirical soot model for the estimation of soot, and an optically thin radiation model for the radiative heat loss from the gas band and soot have also been incorporated into the algorithm. The code has been run with and without incorporating the radiation model for air inlet temperatures of 300 K (non-preheated) and 400 K (preheated). The fuel temperature is kept constant at 300 K. The code has been validated with the experimental results available in the literature. Radiation heat loss decreases the temperature in the computational zone, but does not change the temperature distribution pattern in the case of non-preheated. But when preheated air is used, the decrease in temperature due to radiation heat loss becomes more, and the distribution pattern also changes to some extent. Maximum velocity decreases due to radiation in both cases. There is an ingress of ambient air near the wall in the case of non-preheated which results in higher velocity near the axis. No such recirculation is observed with preheated air and hence the velocity near the axis is also less compared to the non-preheated case. The variation of centerline temperature, velocity, and bulk temperature with axial height has also been shown and discussed for clarification of the abovementioned facts. The effects of radiation are found to be small in both the cases of non-preheated and preheated air. The CO2 and H2O distributions are almost not affected by radiation, although the air preheat affects the distributions of those two species.