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If the calculated hcal is greater than the maximum heat transfer co-efficient of say arbitrary value of 300 Btu/h.ft2℉ for organics and 1000 Btu/h.ft2℉ for water, then what should we do?

Correct Answer: Take hcal= 300 Btu/h.ft2℉ for organics and hcal = 1000 Btu/h.ft2 ℉ for water
The values obtained should be taken equal to it for the next few iterations, this way the calculations would converge to a particular end value.

A stream of air at 100 kPa pressure and 300 K is flowing on the top surface of a thin flat sheet of solid naphthalene of length 0.2 m with a velocity of 20 m/sec. The other data are: Mass diffusivity of naphthalene vapor in air = 6 * 10 –6 m2/sec Kinematic viscosity of air = 1.5 * 10 –5 m2.sc Concentration of naphthalene at the air-solid naphthalene interface = 1 * 10 – 5 kmol/m3 Calculate the overage mass transfer coefficient over the flat plate. Note: For heat transfer over a flat plate, convective heat transfer coefficient for laminar flow can be calculated by the equation. Nu = 0.664 ReL1/2 Pr1/3 you may use analogy between mass and heat transfer.

Experimental results indicate that the local heat transfer coefficient h g for flow over a flat plate with an extremely rough surface is approximated by the relation h x = a x -0.12 Where a is a constant coefficient and x is distance from the leading edge of the plate. What is the relation between this local heat transfer coefficient and the average heat transfer coefficient for a plate of length x?

In a surface condenser, the water flowing through a series of tubes at the rate of 200 kg/hr is heated from 15 degree Celsius to 75 degree Celsius. The steam condenses on the outside surface of tubes at atmospheric pressure and the overall heat transfer coefficient is estimated at 860 k J/m2 hr degree. Find the number of transfer units of the heat exchanger. At the condensing pressure, stream has saturation temperature 0f 100 degree Celsius and the latent heat of vaporization is 2160 k J/kg. Further, the steam is initially just saturated and the condensate leaves the exchanger without sub-cooling i.e. only latent heat of condensing steam is transferred to water. Take specific heat of water as 4 k J/kg K

In a surface condenser, the water flowing through a series of tubes at the rate of 200 kg/hr is heated from 15 degree Celsius to 75 degree Celsius. The steam condenses on the outside surface of tubes at atmospheric pressure and the overall heat transfer coefficient is estimated at 860 k J/m2 hr degree. Find the effectiveness of the heat exchanger. At the condensing pressure, stream has a saturation temperature 0f 100 degree Celsius and the latent heat of vaporization is 2160 k J/kg. Further, the steam is initially just saturated and the condensate leaves the exchanger without sub-cooling i.e. only latent heat of condensing steam is transferred to the water. Take specific heat of water as 4 k J/kg K

The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .

A single pass shell and tube heat exchanger, consisting of a bundle of 100 tubes (inner diameter 25 mm and thickness 2 mm) is used for heating 28 kg/s of water from 25 degree Celsius to 75 degree Celsius with the help of a steam condensing at atmospheric pressure on the shell side with condensing heat transfer coefficient 5000 W/m2 degree. Make calculation for overall heat transfer coefficient based on the inner area. Take fouling factor on the water side to be 0.002 m2 degree/W per tube and neglect effect of fouling factor on the shell side and thermal resistance of the tube wall

A heat exchanger with heat transfer surface area A and overall heat transfer coefficient U handles two fluids of heat capacities Cmax and Cmin. The number of transfer units (NTU) used in the analysis of heat exchanger is specified as

In a counter flow heat exchanger, water flowing through a tube of 10 cm inner diameter is heated by steam condensing on the outside of the tube. The convective film coefficient on the water and steam side are estimated to be 12000 and 20000 k J/m2 hr degree. Neglecting tube thickness and its resistance to heat flow, workout the overall heat transfer coefficient for the heat exchanger

The heat loss from unpainted aluminum side of a house has been calculated on the presumption that overall coefficient of heat transfer is 5 W/m 2 K. Later, it was discovered that the air pollution levels are such that fouling factor on this side is of the order of 0.0005 m2 K/W. Find overall heat transfer coefficient of dirty side

A passage is given with five questions following it. Read the passage carefully and select the best answer to each question out of the given fouralternatives. Teaching about compassion and empathy in schools can help deal with problems of climate change and environmental degradation,” says Barbara Maas, secretary,
Standing Committee for Environment and Conservation, International Buddhist Confederation (IBC). She was in New Delhi to participate in the IBCs governing
council meeting, December 10-11, 2017. “We started an awareness campaign in the year 2005-2006 with H H The Dalai Lama when we learnt that tiger skins were
being traded in China and Tibet. At that time, I was not a Buddhist; I wrote to the Dalai Lama asking him to say that this is harmful and he wrote back to say, “We
will stop this.” He used very strong words during the Kalachakra in 2006, when he said, If he sees people wearing fur and skins, he doesnt feel like living. This sent
huge shock waves in the Himalayan community. Within six months, in Lhasa, people ripped the fur trim of their tubba, the traditional Tibetan dress. The messenger was ideal and the audience was receptive,” says Maas who is a conservationist. She has studied the battered foxs behavioral ecology in Serengeti,Africa. She heads the endangered species conservation at the Nature and Biodiversity Conservation Union (NABU) International Foundation for Nature, Berlin. “I metSamdhong Rinpoche, The Karmapa, HH the Dalai Lama and Geshe Lhakdor and I thought, if by being a Buddhist, you become like this, I am going for it, “says Maas, who led the IBC initiative for including the Buddhist perspective to the global discourse on climate change by presenting the statement, The Time to Act is Now: aBuddhist Declaration on Climate Change, at COP21 in Paris. “It was for the first time in the history of Buddhism that leaders of different sanghas came together to take a stand on anything! The statement lists a couple ofimportant things: the first is that we amass things that we dont need; there is overpopulation; we need to live with contentment and deal with each other and theenvironment with love and compassion,” elaborates Maas. She is an ardent advocate of a vegan diet because “consuming meat and milk globally contributes more toclimate change than all "transport in the world.” Turning vegetarian or vegan usually requires complete change of perspective before one gives up eating their favorite food. What are the Buddhist ways to bringabout this kind of change at the individual level? “To change our behavior, Buddhism is an ideal vehicle; it made me a more contented person,” says Maas, who grewup in Germany, as a sausage chomping, meat-loving individual. She says, “If I can change, so can anybody”. Why did Ms. Barbara Mass say “If I can change, so can anybody”?