Basic Chemical Engineering Knowledge: [One Question per Day] 2010-12-20
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This post was last edited by yunzhongzi112 on 2010-12-19 22:47. Judgment and reasoning question: Generally, for the same pump, when pumping water with a density of 1000 Kg/m3, its head is 10 meters; whereas when using this pump to pump sulfuric acid with a density of 2000 Kg/m3, the pump’s head is 5 meters. () PS:: 1) The top 50 active participants will definitely receive a reward; those who provide detailed analysis, discussions, and derivation processes will get 10-15 Wealth or 1 Charm:victory:. 2) Please hide your replies. The method to do this is: http://bbs.hcbbs.com/thread-492556-1-1.html. Do not edit your replies after posting them{:1_90:}, and also avoid copying others’ answers, as that will result in a penalty:funk: ； Indicate the question number when answering; otherwise, it will be difficult to determine whether the answer is correct: handshake. # V5 m9 3) The reference answers will be visible once you reply; those who want to confirm the answers may refer to: o. 4) Please also avoid submitting answers multiple times maliciously; if it is due to an operational error, please contact the forum moderators or administrators: call:. Otherwise, points will be deducted. 5) Currently, all the daily questions in the section on basic chemical engineering theories have been compiled; interested users can go and take a look and learn from them*. Click directly: Summary post of daily questions in the Basic Theories of Chemical Engineering section (being added). Wrong. The definition of head is as follows: The energy provided by a pumping mechanism to a unit weight of fluid is generally referred to as the head or lift of that mechanism. Therefore, the head is independent of the fluid density, but under the same head, the pressure difference between the inlet and outlet of the pump is proportional to the fluid density.
Wrong. The principles of chemical engineering make it clear that head has nothing to do with density, but the reading on the pressure gauge at the pump outlet is related to density. Pump power is related to density.
This post was last edited by yunzhongzi112 on 2010-12-19 23:10. Correct! The head of a pump is the height to which it can lift liquid; it is related to the density of the liquid being transported as well as to the power used for pumping. For the same liquid, the greater the power, the higher the head; with the same power level, however, the head remains constant. The greater the liquid density, the lower the head; head = power × pump efficiency / flow rate / density / acceleration due to gravity
Reply 1# yunzhongzi112 Error
This post was last edited by xu*ang309 on 2010-12-19 at 23:19. The reason for the error is that the head of a centrifugal pump, also known as the pump’s pressure head, refers to the energy gained by a unit weight of fluid as it passes through the pump. The head of a pump depends on its structure (such as the diameter of the impeller and the curvature of the blades), as well as its rotational speed. At present, the head of a pump cannot be accurately calculated theoretically; it is generally determined by experimental methods. Forgot to hide it; edit again to hide it
Correct. According to P = density * gravitational acceleration * height
This post was last edited by fye002 on 2010-12-20 00:54. Answer: Wrong; it’s not a simple direct proportionality relationship
No, it doesn’t depend solely on density
Wrong: When the same pump is used to transport fluids of different densities, the head remains unchanged, and the pressure indicated by the pressure gauge at the pump outlet also stays the same; only the height to which the fluid can be pumped changes