RESEARCH AND EXPERIMENT OF THERMAL WATER DE-ICING DEVICE ÉTUDE ET EXPÉRIMENTATION DE L ÉQUIPEMENT DE DÉGIVRAGE AU JET D EAU THERMALE

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1 RESEARCH AND EXPERIMENT OF THERMAL WATER DE-ICING DEVICE Zicheng Zhu 1, Xuejun Zhang 1, Qiang Wang 2 and Weijun Chu 2 1 Xinjiang Agricultural University, Urumqi, China 2 PLA University of Science & Technology, Nanjing, China zzc881225@163.com; zhxjau@sina.com Received March 2015, Accepted July 2015 No. 14-CSME-38, E.I.C. Accession 3699 ABSTRACT By analyzing the deficiencies of existing de-icing methods, a new de-icing method which combines thermal de-icing with water-jet cutting de-icing technology is coming into being. This paper introduces the construction of thermal water-jet de-icing equipment. Through repeated experiments, the factors which would affect de-icing have been researched and experimentally verified, including jet pressure, nozzle aperture, standoff, and jet injection angles, etc. Analysis of experimental results shows that this device can perform well and satisfy design requirements. Keywords: thermal water-jet; nozzles; thermal de-icing; MATLAB. ÉTUDE ET EXPÉRIMENTATION DE L ÉQUIPEMENT DE DÉGIVRAGE AU JET D EAU THERMALE RÉSUMÉ En analysant les défectuosités des méthodes existantes de dégivrage, une nouvelle méthode de dégivrage qui combine le dégivrage thermal et la technologie de dégivrage au jet d eau a été créée. Cette thèse présente la construction d équipement de dégivrage au jet d eau thermale. En faisant des expérimentations réitératives les éléments qui ont des effets sur le dégivrage ont été étudiés et vérifiés expérimentalement, y compris la pression du jet, l alésage de la buse, la distance du jet, les angles d injection du jet etc. A la suite du résultat analytique des expérimentations, on a conclu que cet équipement fonctionne bien et satisfait les exigences de design. Mots-clés : jet d eau thermale; buse; dégivrage thermal; MATLAB. Transactions of the Canadian Society for Mechanical Engineering, Vol. 39, No. 4,

2 Fig. 1. (a) The de-icing process by thermal water-jet. (b) The mechanical de-icing process. NOMENCLATURE A P nozzle aperture (mm) jet pressure (MPa) 1. INTRODUCTION Every winter, many areas of China suffer snow and ice. Sanzo and Hecnar [1] found that the snow and ice frozen on the roads would reduce friction and therefore cause serious traffic accidents. In consequence, effective measures must be taken to clear the snow and ice from the roads in time to ensure safety. According to many previous studies, the de-icing technology in foreign countries has been developing gradually, coming up with various kinds of equipments and methods. The most common methods are: mechanical, chemical and thermal method [1]. Each method has its own advantages and disadvantages. The chemical method makes use of de-icer to melt ice and snow but would cause severe environmental contamination and pollution [2, 3]. The mechanical method is excellent in removing the floating snow, but when it comes to the glaciations, the rate of cleaning is low and would easily damage the surface of roads [4, 5]. Presently, the thermal method is under development. The low de-icing speed, poor efficiency, and high energy consumption make it an unwise choice [6]. Among these methods, only a few can perform well, de-ice effectively and cost less. So a new kind of ice-de-icing method is needed that could fully realize the advantages of the mechanical de-icing method, thermal de-icing method and water-jet cutting technology to achieve rapidity, efficiency and economy in ice-de-icing work. 2. STRUCTURE OF THERMAL WATER DEVICE AND NOZZLE The thermal water-jet cutting is used in combination with thermal de-icing and water-jet cutting. When the process is deployed, the ice layer is melted by thermal power, water-jet impingement and some other factors. Through the combination of mechanical shovel blade and thermal water-jet, the ice on the road can easily be cleaned up. Figure 1(a) shows the ice square after cutting by thermal water-jet. Because the ice layer has been cut into independent sections, the shovel blade can easily de-ice these sections after jetting, like Fig. 1(b). Besides, the shovel blade can easily adapt to barriers on the road Thermal Water Device The de-icing equipment mainly consists of heating hybrid system and thermal water-jet cutting system. To cut the pavement ice into independent sections, this paper presents a water tank, in the bottom of which two groups of nozzles are installed, as shown in Fig. 2. There are about nozzles evenly arranged in the 784 Transactions of the Canadian Society for Mechanical Engineering, Vol. 39, No. 4, 2015

3 Fig. 2. Design of thermal water jet device. Fig. 3. (a) Straight conical nozzle.(b) Conical nozzle. line space of each group, and these nozzles can be allocated into two groups: the conical and the straight conical ones Nozzles Structure and Fluid Simulation Analysis Aiming at the research objects of this paper, in Fig. 3, the basic sizes of the two kinds of nozzles are as follows: the inlet diameter D of fluid is 10 mm, the outlet diameter d is 1 mm, the length of outlet cylinder L is 2 mm, and the conical angle α is 80. These are the actual sizes of the nozzles used in the laboratory. Fluid field was simulated and analyzed by ANSYS FLUENT software. As shown in Figs. 4(a) and 4(b), the axial velocity of the conical nozzle is 248 m/s, slightly faster than that of the straight conical nozzle, which is 245 m/s. Similarly, the isokinetic core zone of the former is a little larger than that of the latter. According to the numerical data, the conical nozzle obviously has higher convergence quality, larger turbulent kinetic energy and lower turbulent energy dissipation rate. Transactions of the Canadian Society for Mechanical Engineering, Vol. 39, No. 4,

4 Fig. 4. (a) Distribution of the conical nozzle s axial velocity. (b) Distribution of the straight conical nozzle s axial velocity. Table 1. Data of repeated tests of dual-factors of jet pressure and nozzle aperture. A 1 A 2 A 3 P P P P EXPERIMENTS AND DATA ANALYSIS To obtain the accurate experimental data and validate the feasibility of the device, the low-temperature laboratory is established. In the experiments, the factors which would influence the de-icing effect are jet pressure, nozzle aperture, water-jet temperature, the distance and angle between nozzle and ice surface, the forward and reciprocating speed of the nozzle, shape of the nozzle, motor power, etc. Taking the limitations of the laboratory space and equipments into consideration, indoor experiments mainly analyze the influence of the jet pressure, nozzle aperture, standoff, and jet injection angles Effect of Jet Pressure and Nozzle Aperture to the De-icing Result With conditions where the distance between nozzle and ice surface is 100mm, the jet injection angle is 0, the travel speed is 0.2 m/s, and the temperature of jet flow is in the range of 89 93, we choose different jet pressures and nozzle apertures to conduct the experiments. With repeated tests, we obtain the average groove depth in different nozzle apertures and jet pressures, building average depth tables (see Table 1). Associated with this table, the regression analysis and curve fitting equation can easily be obtained, where A presents the nozzle aperture (A 1 = 0.5 mm, A 2 = 0.75 mm, A 3 = 1.00 mm); P presents the jet pressure (P 1 = MPa, P 2 = MPa, P 3 = MPa, P 4 = MPa). Using SPSS statistical software to analyze the data, the output results are as given in Fig. 5. According to the analysis result, we can obtain the equation of the fitting curve as follows: y = 5.18x x x x x 1 x (1) where y is the groove depth, x 1 is the jet pressure, x 2 is the nozzle aperture. In Eq. (1), it is obvious that the nozzle aperture x 2 has a relationship of quadratic curve with the groove depth y, and the jet pressure x 2 has 786 Transactions of the Canadian Society for Mechanical Engineering, Vol. 39, No. 4, 2015

5 Fig. 5. Curves of groove depth under different nozzle aperture following the pressure change. Fig. 6. Curves of groove depth in different standoff. a linear relationship with the groove depth y when the pressure is changing in MPa. So, when the nozzle aperture is 1.0 mm, the de-icing effect is the best Impact of Standoff and Jet Injection Angles to the De-icing Result According to the water jet theory, the jet injection angles α and standoff h between jet nozzles and ice surface will influence the result. Therefore, in the process of experiments, the two factors were studied. Table 2 shows the difference of groove depth data, under the condition that nozzle aperture is 1.0 mm, the forward speed is 0.2 m/s, the jet temperature is in a small range(89 93 ), the standoff is 100 mm, and the jet pressure is MPa. The positive angles represent that the nozzle tilts along the forward direction of the device. So, the negative angles represent the opposite. From Table 2, we know that the most efficient angle is 15. Figure 6 shows that the groove depth varies with standoff. The experimental conditions are as follows: nozzle aperture is 1.00 mm, the forward speed is 0.2 m/s, the jet temperature is in a small range (89 93 ), the jet injection angles is 15, and the pressure is constant. Transactions of the Canadian Society for Mechanical Engineering, Vol. 39, No. 4,

6 According to the analysis result, we can obtain the equation of the fitting curve as y = 0.003x x (2) where y is the groove depth and x is the standoff. From Eq. (2) and Fig. 6, it is obvious that the most efficient standoff is 110 mm. 4. CONCLUSIONS This article mainly studied the compound de-icing method, designed the thermal water-jet device, and repeatedly conducted indoor experiments to find out the factors affecting the de-icing process. By analyzing the experimental data, we find the effect changes of the compound de-icing device in different jet pressure, nozzle aperture, standoff and jet injection angles, which will provide an effective reference for the further optimization of the equipment to improve the de-icing efficiency. The experiments indicate that this device performs well in de-icing work, is environmentally friendly and satisfies the design requirements. REFERENCES 1. Sanzo, D. and Hecnar, S.J., Effects of road deicing salts (NaCl) on larval woodfrogs, Journal of Environmental Pollution, Vol. 140, No. 2, pp , Olofsson, B. and Lundmark, A., Monitoring the impact of de-icing salt on roadside soils with time-lapse resistivity measurements, Environmental Geology, Vol. 57, pp , Lingenfelder, T., Fischer, K., Sold, M.G. Post, S., Enderle, M.D. and Kaehle, G.F.B.A., Combination of water-jet dissection and needle-knife as a hybrid knife simplifies endoscopic submucosal dissection, Surgical Endoscopy, Vol. 23, No. 7, pp , Cadavid, R., Wustenberg, D., Louis, H., Pude, P., and Senne, T., Effect of helium atmospheres on abrasive suspension water jets, International Journal of Advance Manufacturing Technology, Vol. 26, pp , Silver, P., Rupprecht, H.M. and Stauffer, M.F., Temperature-dependent effects of road deicing salt on chironomid larvae, Wetlands, Vol. 29, pp , Ben Jamintgree, N. and Janoyan, K.D., Use of electrically conductive concrete overlays for passive control of snow and ice on road, in Proceedings IEEE International Conference on Energy, Environment and Disasters, Charlotte, NC, USA, pp , July Zhou, J., Lai, S., Xu, X., Chen, Y., Chu, W. and Gao, Y., R&D of equipment for deicing by thermal water-jet and mechanical deicing method, in Proceedings of IEEE International Conference on Applied Mechanics, Materials and Manufacturing, Changchun, China, pp , November Li, W., Research on Working Mechanism and Parameters Optimization of Roller for the Multifunctional Snow Remover, Dissertation of Jilin University, Changchun, China, pp. 2 8, Deng, H., Ma, W., Jing, B. et al., Technology of removing snow and ice on roads and its developing trend, Construction Machinery and Equipment, Vol. 3, pp , Transactions of the Canadian Society for Mechanical Engineering, Vol. 39, No. 4, 2015