Brake pad is a one of products that plays a role in the automotive parts industry and directly affects safety. Therefore there are many designs of brake pads for product development. This research aims to study the thermal conductivity of brake pads and define the thermal conductivity that appropriate to brake pads and also solve the problem of deterioration of braking automotive parts. To achieve this the 3 different ingredient brake pads from Compact International (1994) Co. Ltd. are studied in terms of the heat transfer behavior. The experimental work was set by simulating a brake on the single dynamometer at the braking speed of 50 100 and 130 km/h. As a results the significant parameters are copper and fillers respectively. It affects the heat transfer behavior by means of applying heat from the contact area between the brake pad and the brake disc to the caliper This knowledge will be used in the design of brake pad ingredients to determine the appropriate conductivity of the brake pads.

The purposes of this study were to investigate the heat transfer and the vibration characteristics caused by front and back vented brake disc which had physically different shapes affecting braking distance. In accordance with the theory of heat transfer the heat transfer rates of two types of brake disc were different and played an important role in the deformation during usage. The single dynamometer was conducted to the experimental work as an engineering tool with boundary conditions according to JASO C406 standard. One degree of freedom (DOF) acceleration signals on the brake caliper were analyzed. The results obviously discovered that the back vented brake disc was able to reduce the vibration up to 43.5% comparing to the front vented brake disc in case of the braking temperature 200C initial breaking speed 50 km/h and the hydraulic pressure of 4 MPa. Besides the hydraulic pressure at 4 MPa generated the maximum vibration. Furthermore the initial braking speed and the braking temperature were also the important factors. Regarding braking distance results the results of the experimental work obviously discovered that the back vented brake disc created braking distance shorter than front vented brake disc. Besides there were important factors as braking temperature hydraulic pressure and initial speed of braking. Especially the high braking temperature caused an increase of deceleration and a decrease of braking distance. Moreover the high hydraulic pressure produced a deduction of braking distance and an increase of deceleration. Finally the initial speed of braking directly varied to the braking distance

การวิจัยนี้เสนอการคำนวณเชิงตัวเลขโดยระเบียบวิธีไฟไนต์เอลิเมนต์ เพื่อหาการกระจายอุณหภูมิที่ ตำแหน่งต่าง ๆ ภายในแบบจำลองของแผงท่อให้ความร้อนขนาด 80x282.5x350 มิลลิเมตร โดยลักษณะของ กลุ่มท่อภายในจัดวางเรียงแบบแนวเหลื่อมกันขนาดเส้นผ่านศูนย์กลาง 10 มิลลิเมตร สำหรับการกำหนดเงื่อนไข ขอบเขตแก่แบบจำลองนั้น กำหนดให้อุณหภูมิที่ทางเข้ามีค่าเท่ากับ 20oC 25oC 30oC และ 35oC ตามลำดับ ส่วนภายในแบบจำลองกำหนดอุณหภูมิที่ผิวนอกของแผงท่อให้ความร้อนคงที่ไว้ที่ 50oC 60oC 70oC และ 80oC ตามลำดับ ส่วนผนังหุ้มฉนวนโดยรอบ (ไม่มีการสูญเสียความร้อน) จากผลการวิจัยจะพบว่าอุณหภูมิที่แตกต่างกัน มากมีผลทำให้เกรเดียนท์ของอุณหภูมิมีค่าสูงขึ้นและลักษณะการเปลี่ยนแปลงของอุณหภูมิภายในแบบจำลองนั้น มีลักษณะเพิ่มขึ้นสู่ภาวะอิ่มตัว นั่นคือ ค่าของอุณหภูมิจะมีค่าเพิ่มตามลำดับและมีอัตราการเพิ่มขึ้นอย่างสม่ำเสมอ และเมื่อเวลาผ่านไปค่าของอุณหภูมิภายในของแบบจำลองจะมีค่าคงที่ หลังจากนั้นไม่ว่าจะเพิ่มเวลามากขึ้น เพียงใดก็ตามค่าของอุณหภูมิที่ตำแหน่งต่าง ๆ ภายในแบบจำลองจะไม่มีการเปลี่ยนแปลง

This research aims to study the parameters have affected the pipe which was studied the heat transfer characteristics of a heat pipe with a mesh wick. The heat pipe made from copper tubes with intemal (ID) as 10 and 12 mm and length of 30 cm which was installed a copper mesh wick inside a tube. Three working fluids are distilled water ethanol and refrigerants-11 (R-11). The filling ratios is 50% with respect to evaporator volume. The operating temperature at the evaporator section is: 50 70 and 90 oC. The condenser section has cooked by water with a flow rate of 0.5 L/min. Then all of the experimental data were compared with the heat pipe without copper mesh wick. It was found that heat pipe at ID 12 mm yielded a better heat transfer rate when compared with heat pipe without a mesh wick. The heat pipe produced a heat transfer rate value of 7.3 W and heat pipe efficiency of 58.5 at evaporator section’s temperature of 90oC. In addition the mesh wicks will help transfer the working fluid in the condenser section return to the evaporator section. The condensed liquid had spread around the walls of the heat pipe. The working fluid was condensed to the evaporator section then affected to a higher heat transfer rate.

In general for the refrigeration the cooling coil is almost used to be the device to decrease the temperature. Thus in order to design heat exchange we should study the heat transfer into the cooling coil. This research proposes the numerical using finite element method for calculating the temperature at any position of the cooling point for considering to porous media. After that to create an algebraic equation fmite element for writing the program to search the solution by estimating the temperature. The research demonstrates that the changing of temperature will be decreased to saturated condition that is the temperature around the region of the cooling coil model edge will be decreased. The longer time the lower temperature around each position will decrease respectively until the temperature at each position inside the model are the same as region of the cooling coil model edge. Therefore this search result can be the basic for the comparison with the similar problem of other