Vol. 20 No. 1 (2005)

A compressor testing device based on vapor compression cycle has been designed and built successfully. Simple and easy operation is the main differences between the device and conventional compressor testing device. A reciprocating compressor performance was tested for two kind of refrigerants; R22 and HCR22 using this device. From the experimental results it is found that the isentropic efficiency can be represented by a two degrees polynomial function. The experimental results also shows that the isentropic efficiency of the compressor using R22 is higher compared to the same compressor…

The aim of this research is to establish an analysis of an air conditioning system in a minibus vehicle cabin through some series of numerical simulations using a Computational Fluid Dynamics software. Two three-dimensional models of the vehicle were used in the simulations. The first model is a minibus without any passenger, and the second model is a minibus with seven passengers. In this research, the passenger model was considered as another cooling load source, therefore an analysis of the cooling effect experienced by passenger was not performed. A calculation of cooling load was also…

Crack branch or kink in piezoelectric body may occur due to mechanical or electric loading. This paper presents the analysis of crack branch for ceramic piezoelectric materials. This type of advanced materials is very advantageous for application in smart structures, measurements device and actuators. Utilizing the extended Stroh Formalism for elastoelectric, the boundary value problems are solved by way of Hilbert Transforms. The explicit expressions for the elastic, electric, stress and electric intesity factor, and strain energi density are presented in integral forms. These integrals are…

This paper presents numerical and experimental study of heat transfer on fins-tube heat exchanger that functioned as an evaporator for coolingof humid air. In this case, change of phase occurred both on air and refrigerant. The proposed numerical analysis is based on the application of mass and energy balances implemented at small control volumes that were part of evaporator. The result of numerical evaluation was then compared to the experimental observation. A good agreement between experimental and numerical results was achieved and the proposed numerical method also could be used as a…

Complex modelling using Finite element method in iterative optimisation process often yield expensive computation. One of the solution is to replace the expensive finite element analysis with a mathematically simpler model, that is using an approximate relations (Metamodel). Here, the approach is used to characterise the mechanical properties of an anisotropic plate from their corresponding natural frequencies. Radial basis functions model has been chosen for the Metamodel to approximate the finite element model generated in ANSYS 6.1 software. Characterisation process is regarded as an…