Tham khảo tài liệu 'convection and conduction heat transfer part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 380 Convection and Conduction Heat Transfer Considering c as pseudo specific heat as c c and combining Eqs. 1 and 2 one obtains Shi Guo 2004 Radovic Lalovic 2005 d pc T 7 fc7T 6 dt The boundary condition applied on the outside of the mold is dT - s w-w 7 Here h is the heat transfer coefficient for air convection and To is the external temperature. The factorial design technique The factorial design technique is a collection of statistical and mathematical methods that are useful for modeling and analyzing engineering problems. In this technique the main objective is to optimize the response surface that is influenced by various process parameters. Response surface methodology also quantifies the relationship between the controllable input parameters and the obtained response surfaces Kwak 2005 . The design procedure of response surface methodology is as follows Gunaraj Murugan 1999 i. Designing of a series of experiments for adequate and reliable measurement of the response of interest. ii. Developing a mathematical model of the second-order response surface with the best fittings. iii. Finding the optimal set of experimental parameters that produce a maximum or minimum value of response. iv. Representing the direct and interactive effects of process parameters through two and three-dimensional plots. If all variables are assumed to be measurable the response surface can be expressed as follows Aslan 2007 Yetilmezsoy et al. 2009 Pierlot et al. 2008 Dyshlovenko et al. 2006 y f xi X2 X3 .Xk 8 where y is the answer of the system and xi the variables of action called variables or factors . The goal is to optimize the response variable y. It is assumed that the independent variables are continuous and controllable by experiments with negligible errors. It is required to find a suitable approximation for the true functional relationship between independent variables or factors and the response surface. Usually a second-order model is utilized in response .
