Question: What Is Counter Flow System?

What is effectiveness of fin?

Effectiveness of fin (εfin): It is defined as the ratio of the actual heat transfer that takes place from the fin to the heat that would be dissipated from the same surface area without fin..

What is the Pacific equatorial countercurrent?

Equatorial countercurrent, current phenomenon noted near the equator, an eastward flow of oceanic water in opposition to and flanked by the westward equatorial currents of the Atlantic, Pacific, and Indian oceans.

How does countercurrent flow work?

This is the way that a fish’s gills absorb the maximum amount of oxygen from the water. Water flows in the opposite direction to the blood flow in the gills to ensure that there is always a higher concentration of oxygen in the water than the concentration of oxygen in the blood.

What is the principle of countercurrent exchange?

Countercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some chemical, between two flowing bodies flowing in opposite directions to each other.

What is fouling factor?

The fouling factor represents the theoretical resistance to heat flow due to a build-up of a layer of dirt or other fouling substance on the tube surfaces of the heat exchanger, but they are often overstated by the end user in an attempt to minimise the frequency of cleaning.

What does countercurrent mean?

1 : flowing in an opposite direction. 2 : involving flow of materials in opposite directions countercurrent dialysis.

Why is countercurrent flow efficient?

Counter flow heat exchangers are inherently more efficient than parallel flow heat exchangers because they create a more uniform temperature difference between the fluids, over the entire length of the fluid path. … For example, one fluid may make 2 passes, the other 4 passes.

What are advantages of countercurrent exchange?

In contrast, countercurrent oxygen exchange allows the blood to pick up 90 percent of the oxygen in the water. This impressive ability to acquire oxygen allows fish to thrive in water that has oxygen levels only a tenth of those at the top of Mount Everest, where most people cannot survive without supplemental oxygen.

What causes equatorial countercurrent?

Equatorial countercurrents, driven by tropical surface wind patterns, flow in the opposite direction of the surface winds. greater than those in the Atlantic. In both the Pacific and Atlantic the equatorial countercurrent is located farthest north in the fall, centered near 8 degrees north.

What is counter flow cooling tower?

In a crossflow tower, air travels horizontally across the direction of the falling water whereas in a counterflow tower air travels in the opposite direction (counter) to the direction of the falling water. See Figure 1 and Figure 2 for a visual explanation.

Can log mean temperature difference be negative?

According to the definition modeled above, LMTD cannot be negative.

Where are counter flow heat exchangers used?

Counter-current Flow: Fluids flow in opposite directions. These are used for liquid-liquid, condensing and gas cooling applications.

What is the advantage of counter flow system?

One of the great advantages of counter-current flow is the possibility of extracting a higher proportion of the heat content of the heating fluid. It is important to note that the LMTD value for counter-current flow is much larger than for cocurrent flow at the same terminal temperature (see Figure 1.9).

What happens when lmtd is zero?

A liquid can be heated, cooled or stabilized by transferring it through a heat exchanger. When the Log Mean Temperature Difference is zero there is no temperature exchange taking place.

Why is lmtd needed?

The log mean temperature difference (LMTD) is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers. … The use of the LMTD arises, straightforwardly, from the analysis of a heat exchanger with constant flow rate and fluid thermal properties.

How do you calculate lmtd?

by definition given above, LMTD for counter current flow = (60-50) / ln(60/50) = 10 / 0.1823 = 54.850C. For co-current heat exchanger, ΔT1 = TH1 – TC1 = 100 – 30 = 700C (At first end hot and cold fluids enter the heat exchanger.) (At the other end hot and cold fluids exit the heat exchanger.)

Is cross flow more efficient or counter flow?

In most cases, a crossflow tower is preferred for several reasons that include, most importantly, overall efficiency and serviceability. However, crossflow towers have a larger footprint so if you are limited in real estate, a counterflow tower, which is taller but has a smaller footprint, may be your only option.

What is the most effective heat exchanger?

Plate exchanger is the most efficient due to turbulent flow on both sides. High heat-transfer coefficient and high turbulence due to even flow distribution are important. However, a plate heat exchanger regenerator is restricted to low viscosities. With high viscosities, a special tubular may be required.