Numerical Simulation of Flow, Heat and Moisture Transfer in Heat and Moisture Exchanger (HME) Devices

Abstract:

Heat and Moisture Exchanger (HME) is a simple solution to the problems of warming and humidification of inspired gases during ventilator treatment. The device acts as an “artificial” nose or passive humidifier, added to the breathing circuit to retain and exchange heat and moisture between inspiration and expiration. The HME traps expiratory heat and moisture from patient’s exhaled breath in a porous medium and returns a portion of them through the subsequent inspiratory cycle. The aim of our paper is to develop a computational fluid dynamics (CFD) model of an HME device commonly used in anaesthesia and intensive care. The CFD results allow a better understanding of flow behaviour leading to the design of more efficient devices. The CFD model solves the gas flow, heat and mass transfer equations in a DAR Hygrobac S (Mallinckrodt DAR, Mirandola, Italy). The temperature, absolute humidity and pressure fields are obtained during expiratory phase to evaluate heat and moisture conserving efficiencies and air flow resistance. The effect of flow rate as one of the major parameters in ventilator setting on temperature, humidity and pressure drop is determined. Inside the HME device, areas of recirculation are observed. As the flow rate increases the output temperature and absolute humidity go up causing a reduction in heat and moisture conserving capacities. Comparison of the CFD results with previously obtained experimental data shows a satisfactory agreement.

• Periodical: Applied Mechanics and Materials (Volume 553)
• Pages: 121-129
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.553.121
• Online since: May 2014
• Authors: Seyed Pezhman Payami, Masud Behnia*, Barry Dixon, John Santamaria, Mehrdad Behnia
• Keywords: Air Flow, Heat Conserving Efficiencies, Moisture Conserving Efficiencies, Moisture Exchanger, Numerical Simulation, Resistance

References

[1] J. Chalon, C. Patel, M. Ali, S. Ramanathan, and H. Turndorf, Humidity and the anesthetized patient, Anaesthesiology, vol. 50, pp.195-198, (1979).

DOI: 10.1097/00000542-197903000-00005

[2] J. M. Hurni, F. Feihl, R. Lazor, P. Leuenberger, and C. Perret, Safety of combined heat and moisture exchangers in long-term mechanical ventilation, Chest, vol. 111, pp.686-691, (1997).

DOI: 10.1378/chest.111.3.686

[3] J. D. Ricard, A. Boyer, and D. Dreyfuss, The effect of humidification on the incidence of ventilator-associated pneumonia, Respiratory Care Clinics of North America, vol. 12, no. 2, pp.263-273, (2006).

[4] R. V. Walley, Humidifier for use with tracheotomy and positive-pressure respiration, Lancet, vol. 1, no. 6926, pp.781-782, (1956).

DOI: 10.1016/s0140-6736(56)91245-4

[5] J. J. J. Lucato, A. B. Adams, R. Souza, J. A. Torquato, C. R. R. Carvalho, and J. J. Marini, Evaluating humidity recovery efficiency of currently available heat and moisture exchangers: a respiratory system model study, Clinics, vol. 64, no. 6, pp.585-590, (2009).

DOI: 10.1590/s1807-59322009000600015

[6] L. Thomachot, X. Viviand, S. Arnaud, C. Boisson, and C. D. Martin, Comparing two heat and moisture exchangers, one hyrophobic and one hygroscopic, on humidifying efficacy and the rate of nosocomial pneumonia, Chest, vol. 114, pp.1383-1389, (1998).

DOI: 10.1378/chest.114.5.1383

[7] P. Markowicz, J. D. Ricard, D. Dreyfuss, et al., Safety, Efficacy and cost-effectiveness of mechanical ventilation with humidifying filters changed every 48 hours: a prospective, randomised study, Critical Care Medicine, vol. 28, no. 3, pp.665-671, (2000).

DOI: 10.1097/00003246-200003000-00011

[8] G. Lloyd, Heat and moisture exchangers: principles of operation, Care of the Critically III, vol. 3, pp.111-113, (1987).

[9] J. D. Ricard, D. Cook, L. Griffith, L. Brochard, Physicians' attitude to use heat and moisture exchangers or heated humidifiers: a Franco-Canadian survey, Intensive Care Medicine, vol. 28, pp.719-725, (2002).

DOI: 10.1007/s00134-002-1285-7

[10] K. E. A. Burns, F. Lellouche, F. Loisel, et al., Weaning critically ill adults from invasive mechanical ventilation: a national survey, Canadian Journal of Anaesthesia, vol. 56, pp.567-576, (2009).

DOI: 10.1007/s12630-009-9124-8

[11] J. P. Roustan, J. Kienlen, P. Aubas, S. Aubas, and J. du Cailar, Comparison of hydrophobic heat and moisture exchangers with heated humidifier during prolonged mechanical ventilation, Intensive Care Medicine, vol. 18, no. 2, pp.97-100, (1992).

DOI: 10.1007/bf01705040

[12] N. Unal, J. K. K. Kanhai, S. L. C. E. Buijk, J. C. Pompe, W. P. J. Holland, I. Gultuna, C. Ince, B. Saygin, and H. A. Bruining, A novel method of evaluation of three heat-moisture exchangers in six different ventilator settings, Intensive Care Medicine, vol. 24, pp.138-146, (1998).

DOI: 10.1007/s001340050535

[13] R. D. Branson, and K. Davis, Evaluation of 21 passive humidifiers according to the ISO 9360 standard: moisture output, dead space, and flow resistance, Respiratory Care, vol. 41, no. 8, pp.736-743, (1996).

[14] W. W. Mapleson, J. G. Morgan, and E. K. Hillard, Assessment of condenser-humidifiers with special reference to a multigauze model, British Medical Journal, vol. 1, pp.300-305, (1963).

DOI: 10.1136/bmj.1.5326.300

[15] ANSYS CFX-Solver Theory Guide, Canonsburg, PA: ANSYS Inc., (2010).

[16] K. H. Clifford, and W. W. Stephen (eds), Gas Transport in Porous Media. Dordrecht, Netherlands: Springer, 2006, ch. 2.

[17] J. L. Niu, and L. Z. Zhang, Membrane-based Enthalpy Exchanger: material considerations and clarification of moisture resistance, Journal of Membrane Science, vol. 189, pp.179-191, (2001).

DOI: 10.1016/s0376-7388(00)00680-3

[18] Covidien (2012). DAR Filters & Accessories [Online]. Available: http: /www. covidien. com.

[19] Polymer Handbook, 3rd ed., J. Brandrup, and E. H. Immergut (eds), John Wiley & Sons Inc., NY, USA, 1989, p.101–170.

[20] S. O. Olutimayin, C. J. Simonson, Measuring and modelling vapour boundary layer growth during transient diffusion heat and moisture transfer in cellulose insulation, International Journal of Heat and Mass Transfer, vol. 48, pp.3319-3330, (2005).

DOI: 10.1016/j.ijheatmasstransfer.2005.02.024

[21] P. Pelosi, G. S. Severgnini, et al., In vitro evaluation of an active heat-and-moisture exchanger: the Hygrovent Gold, Respiratory Care, vol. 55, no. 4, pp.460-466, (2010).

[22] B. Revenas, and C. E. Lindholm, Temperature variations in disposable heat and moisture exchangers, Acta anaesthesiologica scandinavica, vol. 24, pp.237-240, (1980).

DOI: 10.1111/j.1399-6576.1980.tb01542.x

[23] M. Ogino, R. Kopotic, and F. L. Mannino, Moisture-conserving efficiency of condenser humidifiers, Anaesthesia, vol. 40, pp.990-995, (1985).

DOI: 10.1111/j.1365-2044.1985.tb10554.x