Desi gn of the protection clothes

17.5.1 Desi gn of the protection clothes

The calculations were performed for five elements of the human body shown in Fig.17.1. Thermodynamic properties of the body layers are given in the table 17.4. Usually, the ice protection construction consists of the ice layer separated from the surrounding medium by several layers. In the present work we used three layers: outer clothing layer with thickness of 0:001m, iso- lating layer of 0:009m and the air layer of 0:003m. All layers have the initial

0 D temperature T 0

19 . The air gap between the ice and the underwear of the thickness 0:0025 m was 0:003 m thick. The human body was 180 cm in height with the mass of 80 kg. The full description of the input data can be found in [41]. It was assumed that the test person does the work at a rate of about M D 420 watts. Additional heat release due to this work was taken into account during numerical simulations in the heat production rate f .x/

(see Eq. (17.4)).

Brain power

By 2020, wind could provide one-tenth of our planet’s electricity needs. Already today, SKF’s innovative know-

how is crucial to running a large proportion of the world’s wind turbines.

Up to 25 % of the generating costs relate to mainte- nance. These can be reduced dramatically thanks to our systems for on-line condition monitoring and automatic lubrication. We help make it more economical to create cleaner, cheaper energy out of thin air.

By sharing our experience, expertise, and creativity, industries can boost performance beyond expectations. Therefore we need the best employees who can meet this challenge!

The Power of Knowledge Engineering

Plug into The Power of Knowledge Engineering. Visit us at www.skf.com/knowledge

180 Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more Click on the ad to read more

Table 17.4: Thermodynamic coefficients of the body layers used in simula- tions

layer heat

heat capacity, conductivity,

temperature, production, KJ/K 3 W/(mK) kg m Deg. Celsius

W core

36.89 76.24-80.00 muscles

39.97 0.4186

1050

36.28 8.30-9.00 fat

74.68 0.3959

1050

34.53 3.57-4.00 skin

The numerical simulations are used to find the distribution of the ice thick- ness necessary to keep the body core (both inner an outer) temperature at less

0 than 36:7 0 ˙1 within one hour at the temperature of surrounding medium of

50 0 . The numerical results were utilized to design a special protection jacket for rescue team working under emergency conditions in the mining industry.

Since the continuous distribution of the ice protection is difficult from the technology point of view and undesirable from ergonomics considerations the jacket protection was designed using the discrete distribution of the ice in form of briquettes embedded into the jacket (see Fig. 17.4). The further simulations have been performed to prove the ability of the new designed jacket to satisfy the protection requirements. Fig. 17.5 illustrates the tem- perature distribution around the human body in centers of the upper and the lower elliptical cylinders shown in Fig. 17.1. The discrepancy between the

desirable temperature 36:7 0 corresponding to the continuous ice distribution and the actual temperature corresponding to the discrete ice distribution can

be considered as acceptable. Therefore the jacket designed on the base of numerical simulations was manufactured and tested in further experimental investigations.