Vol. 23 No. 1 (2008)

This paper describes the development of experimental testing system and performance measurement of small turbojet engine “Olympus” manufactured by AMT Netherlands. Variables that measured in the measurement are turbine exit gas temperature, fuel and air mass flow, compressor rotational speed, and thrust produced. In this testing, the thrust generated by the engine is measured using bending beam load cell that completed with four strain gauge (each load cell completed with two strain gauge). Strain gauge used in this testing is manufactured by Measurement Group, Inc with gauge factor 2.095 ±…

Trimethylolethane (TME) trihydrate slurry is a proper phase-change material for latent heat transportation in cooling systems since it has excellence heat transfer performance and high thermal capacity. Additives, oleyl bishydroxyethyl methyl ammonium chloride (as surfactant) and sodium salicylate (as counter-ion), were used as drag-reducer substance. These additives not only induce drag reduction in TME slurry, but also control particle growth and agglomeration. In this study, energy saving estimation of drag-reducing TME slurry application in district cooling system is invesitgated. It is…

"Ahmed Body" is a well-established model of a hatchback car. In this study, computational simulations were conducted by using existing CFD software to capture "drag crisis" phenomena. Flow is assumed as incompressible flow with Reynolds Number of 4.3 x 10^6. A half of "Ahmed Body" was used in computational simulations with RANS method. Turbulence models that were employed mostly are k-e. The amount of grid cells used in computation is about 300.000. Computations were carried out mostly to get drag coefficients and also to examine vortex structure related to it. In "drag crisis" phenomena,…

This paper derives mathematical equation describing the relation between errors in FRF due to limited record time length, record time and the time constant of a vibration system modelled by the I- dof vibration system with viscious damping. It is assumed in derivation of the equations that both impact excitation as well as response signals are not contaminated by noises. Moreover, the impact excitation is assumed to be a delta Dirac function. Consequently, the spectrum of the excitation is constant for all frequencies. The derived mathematical equations results show that the FRF error is a…

This study deals with numerical investigation of hydrodynamic properties of fluids flow accross a single circular cylinder. The flow is assumed incompressible, laminar with Reynolds number 0,0001, 2, 20, 40, 100, 200, 400, 1000, 4000 and 20000. The work started with generating geometrical mesh, and then continue with the numerical simulation. The simulations were done by varying the pressure with standardm linier or second order interpolation, momentum discretisation (first-order upwind, second-order upwind, Power law), and pressure velocity coupling (SIMPLE, SIMPLEC, and PISO). The…