A parametric study of the thermal performance during charging of a full-scale radial inlet diffuser in a cylindrical stratified chilled water storage tank was performed by applying factorial experimental theory to the results of simulations performed with a validated computational fluid dynamics (CFD) model. Part 1 describes the development and validation of the CFD model. Part 2 summarizes the...

the monolithic catalytic converter is still the main pollution control device for modern vehicles in order to reach the ever-increasing legislative demands for low emission standards. the catalytic converters require a large expansion from the exhaust pipe to the front face of the monolith. unfortunately, packaging constraints often do not permit the use of long diffusers. hence, flow separatio...

Flow characteristics of low Reynolds number laminar flow through gradually expanding conical and planar diffusers were investigated. Such diffusers are used in valveless micropumps to effect flow rectification and thus lead to pumping action in one preferential direction. Four different types of diffuser flows are considered: fully developed and thin inlet boundary layer flows through conical a...

The monolithic catalytic converter is still the main pollution control device for modern vehicles in order to reach the ever-increasing legislative demands for low emission standards. The catalytic converters require a large expansion from the exhaust pipe to the front face of the monolith. Unfortunately, packaging constraints often do not permit the use of long diffusers. Hence, flow separa...

A computational fluid dynamics (CFD) model has been developed to simulate the flow and heat transfer near a lower radial inlet diffuser in a cylindrical stratified chilled water storage tank during charging. The model was used to perform parametric simulations of inlet diffuser performance in full-scale tanks during thermocline formation, from which first-order correlation relating thermal perf...

This paper studies the effects of viscous loss, flow separation and base pressure for ducted turbine designs using computational fluid dynamics (CFD) simulation. Analytical model coefficients for inlet and diffuser efficiency and base pressure coefficient parameterize these effects and have been identified from CFD results. General trends are: the inlet efficiency is nearly unity for the simula...

The prevention of airborne infections in emergency departments is a very important issue. This study investigated the effects of architectural features on airborne pathogen dispersion in emergency departments by using a CFD (computational fluid dynamics) simulation tool. The study included three architectural features as the major variables: increased ventilation rate, inlet and outlet diffuser...

The effects of the diffuser vane on the performances of the multistage centrifugal pump were investigated experimentally, taking account of the interactions among the diffuser vane, the return vane, and the next stage impeller. It is very important to match well the diffuser vane with the return vane, for improving the hydraulic efficiency of the pump. The efficiency may be more improved by mak...

Influence of diffuser vane position on dangerous blade vibration due to blade flow interactions at part load operating condition was investigated in a centrifugal compressor. By means of some measurement and analysis techniques a mechanism of interaction between blade vibration and circumferential flow condition in the impeller with vaned diffuser was determined, which is a cause of dangerous b...

In this paper some discrete parts of an electrostatic and flat-walled self-aligned valveless, micropump for drug delivery system is designed and simulated. The core component of the system is a piezoelectric diaphragm that can convert the reciprocating movement of a diaphragm actuated by a piezoelectric actuator into a pumping effect. The deflection in the diaphragm was analyzed by applying the...