A High-Pressure Droplet Model for Spray Simulations
A High-Pressure Droplet Model for Spray Simulations
复制标题
用于喷雾模拟的高压液滴模型
DOI：
10.1115/1.1915390
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发表时间：
2006
影响因子：
1.5
通讯作者：
S. Aggarwal
中科院分区：
文献类型：
--
作者：
C. Yan;S. Aggarwal
目前用于模拟喷雾的液滴蒸发模型是基于准定常低压配方。这些模型不能充分代表许多高压的影响，如非理想气体的行为，溶解性的气体到液体中，压力依赖性的气相和液相的热物理性质，和瞬态液滴内部的液体传输。在本研究中，高压准稳态液滴蒸发模型开发用于全面的喷雾模拟，更严格的蒸发模型，如那些基于非稳态配方，超出了目前的计算能力。除了保留在模型中的气相准定常假设，该模型纳入了所有的高压效应。通过与现有的实验数据和更全面的瞬态模型的预测结果进行比较，评估了该模型在柴油机和燃气涡轮机燃烧环境中预测液滴蒸发的适用性。结果表明，一个相当好的协议之间的准稳态（QS）和瞬态（TS）模型在较低的环境温度下的广泛的压力范围内，并在高的环境温度下的燃料临界压力的压力。与TS模型相比，QS模型通常在液滴寿命的早期部分低估蒸发速率，而在寿命的后期部分高估蒸发速率，并且在较高的环境压力和温度下，差异变得越来越显著。的差异可以归因于准稳态气相平均温度和组成的QS模型，减少和增加气相的热量和质量通量在液滴表面的假设在早期和后期的部分寿命，分别。QS模型的适用性量化的最大压力作为环境温度的函数。
Droplet vaporization models that are currently employed in simulating sprays are based on a quasisteady, low-pressure formulation. These models do not adequately represent many high-pressure effects, such as nonideal gas behavior, solubility of gases into liquid, pressure dependence of gas- and liquid-phase thermophysical properties, and transient liquid transport in the droplet interior. In the present study, a high-pressure quasisteady droplet vaporization model is developed for use in comprehensive spray simulations for which more rigorous vaporization models, such as those based on unsteady formulations, are beyond the present computational capabilities. Except for the gas-phase quasisteady assumption that is retained in the model, the model incorporates all high-pressure effects. The applicability of the model for predicting droplet vaporization in diesel and gas turbine combustion environments is evaluated by comparing its predictions with the available experimental data and with those from a more comprehensive transient model. Results indicate a fairly good agreement between the quasisteady (QS) and transient (TS) models for a wide range of pressures at low ambient temperatures, and for pressure up to the fuel critical pressure at high ambient temperatures. The QS model generally under-predicts the vaporization rate during the earlier part of droplet lifetime and overpredicts during the later part of lifetime compared to those using the TS model, and the difference becomes increasingly more significant at higher ambient pressure and temperature. The differences can be attributed to the quasisteady gas-phase average temperature and composition assumption for the QS model that reduces and increases the gas-phase heat and mass fluxes at the droplet surface during the earlier and later part of lifetime, respectively. The applicability of the QS model is quantified in terms of the maximum pressure as a function of ambient temperature.