Thermal Analysis of the Car Seat due to the

Arrangement of Hot Wire

Jae Ung Cho1

1Division of Mechanical & Automotive Engineering, Kongju National University, 1223-24,

Cheonan Daero, Seobuk-gu, Cheonan-si, Chungnam of Korea 31080, jucho@kongju.ac.kr

Abstract. Various types of car seats are selling in the market and their levels of

heat transfer differ according to the arrangement and form of inner hot wires.

To find out the change due to the difference of arrangement, we conducted a

thermal analysis by arranging the hot wires in different ways, while at the same

time retaining the distance between the hot wire and the car seat. As a result,

data related to temperature distribution and heat flux after 60 seconds was

attained. In this analysis, models using the CATIA program were made and

thermal analysis using the ANSYS program was conducted.

Keywords: Arrangement of hot wires, Car seat, Thermal analysis, Temperature

distribution, Heat flux, Analysis of normal state, Transition analysis

1 Introduction

In this research, we will analyze temperature distribution and heat flux of car seats

according to different arrangement of hot wires. We also measure changes in

temperature distribution and heat flux after 60 seconds of extreme conditions to verify

the safety. We verify the credibility of our research by comparing and revising results

of three different arrangements of hot wires. The model used in the analysis is the

CATIA version and the analysis was conducted under the ANSYS version. We hope

that our research results can be applied to the arrangement of hot wires and prevent

various types of safety accidents. And these results make it useful for investigating

and predicting the efficiency of hot wires in car seats[1-5].

2 Model and Analysis

2.1 Research Model

We referred to the shape of actual seats and used CATIA to shape the model, and

analyzed the model using ANSYS. The shapes of meshes are presented as Fig. 1(a),

Fig. 1(b) and Fig. 1(c).

Advanced Science and Technology Letters Vol.118 (Mechanical Engineering 2015), pp.54-58

http://dx.doi.org/10.14257/astl.2015.118.11

ISSN: 2287-1233 ASTL Copyright © 2015 SERSC

(a) Model 1 (b) Model 2 (c) model 3

Fig. 1. Mesh of models.

2.2 Thermal Analysis

To analyze the temperature change and heat flux when a specific level of temperature

is set to the hot wires, we made the following settings. The restriction of Fig. 2 is the

convection current to the outer layer of the seat and the temperature of the outside of

entire heat lay is set at 60℃.

(a) Model 1 (b) Model 2 (c) Model 3

Fig. 2. Convection conditions of models.

Fig. 3(a),(b),(c) are the conditions of the normal initial state and show the

temperature distributions of the disc plate at the initial stage. The temperature

distributions are shown from 52.74 to 60.387℃, from 52.65 to 60.354℃, and from

50.254 to 60.682℃ at Fig. 3(a), Fig. 3(b) and Fig. 3(c) respectively.

Advanced Science and Technology Letters Vol.118 (Mechanical Engineering 2015)

Copyright © 2015 SERSC 55

Also, Fig. 4(a),(b),(c) show the distributions of heat flux of the normal initial state.

Around the outer edge of the seat where passengers' bottoms are in touch with, Fig.

4(a), Fig. 4(b) and Fig. 4(c) indicate 0.0066153 W/㎟, 0.0067878 W/㎟ and

0.0080401 W/㎟ respectively.

(a) Model 1 (b) Model 2 (c) Model 3

Fig. 3. Contour of temperature at initial state.

(a) Model 1 (b) Model 2 (c) Model 3

Fig. 4. Contour of total heat flux at initial state.

Fig. 5(a),(b),(c) are stages of transition, showing the heat distribution of the seat's

outer layer after 60s. The temperatures of the seat's outer layers are 52.738~59.641℃

in Fig. 5(a), 52.649~59.638℃ in Fig. 5(b), and 50.254~ 59.566℃ in Fig. 5(c). Fig.

6(a),(b),(c) are also stages of transition, showing the heat flux of the seat's outer layer

after 60s. The heat fluxes around the edge of the outer layer (where passengers'

bottoms are in touch with) are 0.0036263 W/㎟ for Fig. 6(a), 0.0036598 W/㎟, for

Advanced Science and Technology Letters Vol.118 (Mechanical Engineering 2015)

56 Copyright © 2015 SERSC

Fig. 6(b), and 0.003875 W/㎟ for Fig. 6(c). In comparison of the initial stage and the

state after 60 seconds, the temperature of car seat is more widely spread in model 1

than in models 2 and 3, although the difference is minimal. On the other hand, heat

flux of model 3 has decreased more than that of models 1 and 2, thereby proving more

stability. We have concluded that the optimum arrangement of hot wires in car seats

can be found with these results.

(a) Model 1 (b) Model 2 (c) Model 3

Fig. 5. Contour of temperature at transient state(elapsed time of 60sec).

(a) Model 1 (b) Model 2 (c) Model 3

Fig. 6. Contour of total heat flux at transient state(elapsed time of 60sec).

3 Conclusion

The conclusions induced from this research by analyzing the relationship between

temperature and heat flux of three models with different arrangements of car seats are

as follows:

Advanced Science and Technology Letters Vol.118 (Mechanical Engineering 2015)

Copyright © 2015 SERSC 57

(1) At normal initial states, the temperature distribution of outer layer of car seats is

from 52.74 to 60.387℃ in model 1, from 52.65 to 60.354℃ in model 2, and from

50.254 to 60.682℃ in model 3. The maximum level of heat flux around the edge of

the outer layer is 0.0066153 W/㎟ for model 1, 0.0067878 W/㎟ for model 2, and

0.0080401 W/㎟ for model 3.

(2) In comparison of the initial stage and the state after 60 seconds, the temperature of

car seat is more widely spread in model 1 than in models 2 and 3, although the

difference is minimal. On the other hand, heat flux of model 3 has decreased more

than that of models 1 and 2, thereby proving more stability. We have concluded that

the optimum arrangement of hot wires in car seats can be found with these results. We

hope that our research results can be applied to the arrangement of hot wires and

prevent various types of safety accidents. And these results make it useful for

investigating and predicting the efficiency of hot wires in car seats.

Acknowledgments. “This work was (partly) supported by Advanced Motor Parts

Regional Innovation Center (AMP.RIC) of Kongju National University administered

by MKE (Ministry of Knowledge Economy), Korea."

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