Microchannels single

FLOW REGIMES IN MICROCHANNEL SINGLE-PHASE GASEOUS FLUID FLOW... 

Bayazitoglu, Y., and Kakac, S., (2005) Flow Regimes in MicroChannel Single-Phase Gaseous Fluid Flow, Microscale Heat Transfer-Fundamentals and Applications, S. Kakae (ed.), Kluwer Academie Publishers, Dordrecht (This publication). 

The scientific program starts with an introduction and the state-of-the-art review of single-phase forced convection in microchannels. The effects of Brinkman number and Knudsen numbers on heat transfer coefficient is discussed together with flow regimes in microchannel single-phase gaseous fluid flow and flow regimes based on the Knudsen number. In some applications, transient forced convection in microchannels is important. 

Heat transfer in microchannel flow Single-phase convective flows in microchannels Single-phase forced convection in microchannels... 

Bayazitoglu Y, Kakac S (2005) Flow regimes in microchannel single-phase gaseous fluid flow. In Kakac S, Vasiliev L, Bayazitoglu Y, Yener Y (eds) Microscale heat transfer-fundamentals and applications. Kluwer Academic Publishers, The Netherlands... 

A fuller description of the microchannel plate is presented in Chapter 30. Briefly, ions traveling down the flight tube of a TOF instrument are separated in time. As each m/z collection of ions arrives at the collector, it may be spread over a small area of space (Figure 27.3). Therefore, so as not to lose ions, rather than have a single-point ion collector, the collector is composed of an array of miniature electron multipliers (microchannels), which are all connected to one electrified plate, so, no matter where an ion of any one m/z value hits the front of the array, its arrival is recorded. The microchannel plate collector could be crudely compared to a satellite TV dish receiver in that radio waves of the same frequency but spread over an area are all collected and recorded at the same time of course, the multichannel plate records the arrival of ions not radio waves. 

An assemblage (array) of single-point electron multipliers in a microchannel plate is designed to detect all ions of any single m/z value as they arrive separated in time. Thus, it is not necessary for each element of the array to be monitored individually for the arrival of ions. Instead, all of... 

A typical single microchannel electron multiplier. Note how the primary ion beam causes a shower of electrons to form, The shower is accelerated toward the other end of the microchannel, causing the formation of more and more secondary electrons. 

After the analyzer of a mass spectrometer has dispersed a beam of ions in space or in time according to their various m/z values, they can be collected by a planar assembly of small electron multipliers. There are two types of multipoint planar collectors an array is used in the case of spatial separation, and a microchannel plate is used in the case of temporal separation. With both multipoint assemblies, all ions over a specified mass range are detected at the same time, or apparently at the same time, giving these assemblies distinct advantages over the single-point collector in the analysis of very small quantities of a substance or where ions are produced intermittently during short time intervals. 

Kandilikar SG, Upadhye H (2005) Extending the heat flux limit with enhanced microchannels in direct single-phase cooling of computer chips. In Proceedings of 21st SemiTherm Symposium, San Jose, 15-17 March 2005, pp 8-15... 

Wojtan L, ReveUin R, Thome JR (2006) Investigation of saturated critical heat flux in a single, uniformly heated microchannel. Exp Thermal Fluid Sd 30 765-774... 

The problems of micro-hydrodynamics were considered in different contexts (1) drag in micro-channels with a hydraulic diameter from 10 m to 10 m at laminar, transient and turbulent single-phase flows, (2) heat transfer in liquid and gas flows in small channels, and (3) two-phase flow in adiabatic and heated microchannels. The smdies performed in these directions encompass a vast class of problems related to flow of incompressible and compressible fluids in regular and irregular micro-channels under adiabatic conditions, heat transfer, as well as phase change. 

The subject of this chapter is single-phase heat transfer in micro-channels. Several aspects of the problem are considered in the frame of a continuum model, corresponding to small Knudsen number. A number of special problems of the theory of heat transfer in micro-channels, such as the effect of viscous energy dissipation, axial heat conduction, heat transfer characteristics of gaseous flows in microchannels, and electro-osmotic heat transfer in micro-channels, are also discussed in this chapter. 

Lee PC, Tseng FC, Pan C (2004) Bubble dynamics in microchannels. Part 1 single microchannel. Int J Heat Mass Transfer 47 5575-5589... 

While the manifolds were fabricated by a plain molding process, the microchannels substrate fabrication was quite complicated and was achieved by a multistage process. The following main stages were used in the process (1) double side oxidation of a 525 pm (1 0 0) silicon substrate to 1,000 A, (2) single side 1,200 A silicon nitride deposition, (3) silicon nitride channels template opening by reactive... 

Heat transfer in laminar single-phase, two-stream microchannels has been well described in the literature [33, 39-41]. The challenge for medium- to large-scale processes is an added complexity if more than two fluids are required and also the micromanifold region. 

The time resolution of a phase fluorometer using the harmonic content of a pulsed laser and a microchannel plate photomultiplier is comparable to that of a single-photon counting instrument using the same kind of laser and detector. 

A much better time resolution, together with space resolution, can be obtained by new imaging detectors consisting of a microchannel plate photomultiplier (MCP) in which the disk anode is replaced by a coded anode (Kemnitz, 2001). Using a Ti-sapphire laser as excitation source and the single-photon timing method of detection, the time resolution is <10 ps. The space resolution is 100 pm (250 x 250 channels). 

---